with the latency zappers designed into studio one,
paired with a presonus device,
you would be in the sweet spot.
 
i use a rme babyface pro,
with studio one,
and depending on the size of the project and how many active plug'ins i have going,
i can always monitor thru the babyface pro and never have latency issues.
 
with low tracks, no  plugs, i can do direct guitar recording using IR's, 
and still have next to nothing latency going THRU studio one.
 
studio one is optimized for presonus devices.
so there's that.

Blades
Hmmm, that Focusrite Clarett 8pre USB looks nice, but I'm not sure that for the extra $300 I'd be getting something definitively better than the Presonus Studio 1824.  I am not STUCK to the budget, but I need to be compelled to purchase something more than that. 
 

I'am not an expert but I had a presonus firestudio project and I was very happy with it (It still works like a charm in windows 10), then I bought a focusrite scarlett 18i20 and really noticed an improvement. In my opinion, scarlett preamps are a small step above xmax preamps in presonus units (at least to my taste), the preamps in the clarett range are better than both.
Not sure if $300 better though.

Wouldn't touch Behringer for audio interface - even though I believe converters these days are all around the same level. This will be disputed by some, but there are only a handful of converter manufactures in the world. Most mid priced units source their converters from the same source. And unless you're recording a Stradivarius or something of that Ilk and also you're not feeding the recorded signal in and out of the box for outboard effects...then apart from Behringer they will all do the same thing more or less. On saying that you can't go past Motu or Presonus. I've still got my Moto 828 Ultralite 2 from 2010. The LCD light is bust and I had to replace power pack, but apart from that...still does the job. I'm looking at the Quantum units later in the year because I have a gaming laptop with a Thunderbolt port...its one of the newer ports or Thunderbolt 3 so I would have to get an adapter...but if you've got a box computer then the 100 buck thunderbolt card investment would be worth it I think. For me anyway because - Guitar Amp sims. Just make sure you check chipset compatibility - as in the past I believe Presonus audio interfaces can be a bit sensitive.

The only USB interface (that's not RME MOTU $$$$) I would consider "low latency capable" is the Zoom UAC series.   Some issues with non Intel chipset MB.   The 8 channel is $599US
 
 
https://www.zoom.co.jp/pr...usb-30-audio-converter
 
The USB 3.0 SuperSpeed transfer protocol used by the UAC-8, with a speed of 2.0 ms roundtrip @ 96kHz / 32 samples, is ten times faster than USB 2.0 and six times faster than FireWire 800. That not only ensures low latency, it provides a data stream that's unaffected by computer jitter (slight variations in timing), so there's no need to connect an external master clock source.

For the concerns you have, you can simply purchase from a retailer who has a liberal return policy and test run the crap out of it for a while and then commit (or not). Pretty much everyone has a 30-day return policy anymore, and even moderate AIs have more than sufficient latency leeway. A lot of people who complain about latencies are not due to the AI itself, but the plugins and processing power they have running on the transport... in that regard, Studio One has an upper hand with their low latency audio engine setting. The Presonus 1824 would have the added advantage of being optimized for Studio One.
 
A guy who works in the office next to mine habitually buys stuff in 3s, then returns the two lowest performers before the return period is up. He is funny to listen to, since that is definitely the "extreme" approach to product comparison. The eye opener (for me) is the occasions where he determined that the cheapest option was the best performing.

@cityrat - thanks for that new suggestion.  I was initially interested and even a little excited to have another possible contender, but then search after search I found people complaining about two things: stability and crackling/popping.
 
Of course, no one wants either of those, and my current Layla Interface has neither problem.
 
Still leaning towards the Presonus at this point, but the Focusrite is a definite contender.  Looking forward to additional thoughts on the matter.

Audio Interface Shopping List      MY SHOPPING GUIDE  FOR INTERFACES Word Document File
There is a lot of choices
Most important is to make out a list of your requirements first  then start shopping. .
 
Here is a basic outline of hat you will be comparing: 
 
What kind of connectivity do you require? and how many of each.
These are some of the options:
XLR, 1/4" TS, 1/4"TRS, Combi jacks,  RCA, ¼” line level, ¼” Instrument level,
MIDI, SPDIF,  ADAT, MADI , Word Clock.
How many ins and outs do you think you'll need now and in the future?
Are they accessible?  Front or rear panel or both?
Are the ¼” jacks Balanced?  
Is there a true stereo pair? Some don’t have a matched set of inputs which rules out using a pair of mikes on an Acoustic guitar,  drum overheads or recording a stereo source like a hardware synth.
Most interfaces have at least 2 matched combi jacks on the front which is my preference. They can handle just about anything including  XLR and guitar cables. I also think 4 inputs is minimum as it's great not to have to always swap out cables. The extra 2 can be back panel TRS.  If like me you play a few different instruments then having a dedicated input for each is the way to go. If you don't plan on recording bands and your only going to be recording 2 or 3 tracks at once then a 4 channel interface is all you need. You can always add more dedicated inputs buy purchasing a small mixer. If you are going to record a group or band, then 8 XLR inputs will be minimum.
 
Pre Amps are very important and choosing the quality of your needs will take a bit of research.  The “you get what you pay for”  rule applies here, but check out the reviews and keep in mind that if you have those back panel TRS jacks you can always add a hardware pre amp latter. If pre amps are high on your list then look at the $400 plus range. 
Having SPDIF is a nice option as a lot of powered monitors now have digital inputs. Only down side is the monitor control knob on the front panel probably won't control your room level.
On my 2 interfaces SPDIF input does not have direct monitoring either.
 
If you have other gear that supports the various multi channel digital formats like MADI or ADAT then you'll defiantly be requiring those options as in/outs.
Old school MIDI ports are now often replaced with MIDI over USB but if you plan on using any older midi equipment make sure you have this option.
 
I like to have 4 outputs. Main 1/2  to monitors, 3/4 I run to a small mixer I use for monitoring.  If your thinking about recording a group of musicians  then you will need more outputs or headphone mixes. Most multi output interfaces come with GUI based mixing software that facilitates complicated cue mixes. There are also many complaints about the learning curve for using this software so pay attention to reviews.
 
A/D convertors are generally good these days. There would seem to be a diminished return formula at play as the ones that claim highest quality are $$$$$. How much better those will make your recordings is anyone's guess. Myself convertors are low on my list of concerns.
 
Are there peak level meters or just a little LED for each input?  I hate little lights, but that's seems to be standard.
Are there channel Insert jacks?  This is a must if you desire a hardware compressor or EQ. You can also tap into this to run the signal to a monitor/ headphone  mixer. 
 
Are there separate controls for Monitor level and headphone level? This is super important. People who miss this end up having to fork over an extra $100 for a "Big Knob"
Is there a blend control on the front panel for mixing Source with Computer ( DAW) ? Sometimes this is Software based only. This might be important to you to balance the input signal with the playback. I use my small mixer.
How many Headphone jacks? A level for each?
Are the input pads or line / Instrument toggle switches on the front, back or software controlled?
 
Is it a metal box or cheap plastic? Is it light and portable or large and bulky, Rack mountable? Size matters. I like the Tascam interfaces as example, but compared to most others they are way to bulky to pack in a laptop bag.
Does it have an on / off switch? Nice to not have to unplug the wall wart.
 
Does it use Buss power or a power supply? Buss power can have issues with noise and Phantom power. I myself would avoid any interface that does not have an optional A/C power supply.   
 
Does it have DSP effects built in? Certainly a worthwhile option if you plan on using the interface as a live mixer. My next interface I'm looking at is a Motu that serves double duty as a live digital mixer.
Does it use a GUI mixer? Having a software (GUI) mixer adds more options. And once again with brands like the Motu you now have Tablet / iPad remote mixing capabilities which for live sound in ears and studio headphone mixes is pretty slick. 
 
Can it be used as stand alone? Some interfaces are also handy as a small mixer.
What are the Round Trip Latency (RTL) specs? Do you need low RTL for real time processing?
Low RTL is going to be at a higher price point. A $200 interface will have hidden buffers etc and score higher latency. If you wish to use Guitar Sims your going to want to spend more money and get your RTL down to below at least 5ms. Best performers are brand like Motu and RME.
 
Zero Latency monitoring is not the same as RTL. All interfaces have some latency. 
Zero latency is just marketing hype for monitoring directly from the interface.
And most important of all, Does it have top notch drivers for your OS. 
What is the word on support from the company?
Does it come with free software, An LE version of a  DAW you would like to try?  Free plug ins?
 
Everyone will recommend the interface they have chosen, that doesn't mean it is the right one for you.
Sit down and make a list of your desires and then go on web sites like Sweetwater and read reviews and specs. Also a good idea to visit the web sites of the major brands and see what's new. Careful of outdated gear.
 

Well - I pulled the trigger this evening.
 
A little history:
I had a vintage set of Vibraphones (a Premier 701 set to be exact).  I was able to list and sell them on eBay.  They were my sister's and they have been literally sitting in storage (my house) for the past 30 or so years doing nothing.  I spent some time cleaning them up.  I got more than expected for them and after fees and the (painful) shipping, I was left some money, which I promised myself would be used on musical equipment I wanted.
 
I initially expected to spend it on a new set of ATV Electronic hi-hats and a Presonus Faderport 8.  I didn't anticipate having enough left to get the audio interface and expected that I would be waiting on the sale of a few other items to do the interface part.
 
Well, I found an "open box" on the Faderport 8 (eBay from a music store in NY) and the same on the hi-hats (from eDrumCenter in TN), which left me just a little bit short of getting the Presonus Studio 1824.  So, I searched around for a deal - but this is a BRAND new unit, so I was not able to find anything, except a coupon code that offered 15% off $299 or more at musiciansfriend.  It didn't work, but I got a rep on chat and on a Sunday night at 8:00pm and I was able to get that rep to use the discount code.  They couldn't do PayPal as I had hoped (since that's where the eBay purchase funds were sitting), but I was able to do a few transfers and get it done over the phone. 
 
It amounted to about a $75 discount!
 
Don't underestimate the value of looking around and ASKING!
 
So, for a piece of equipment I had sitting in my back room for decades that I not only never used, but also would never use in the future, I was able to purchase a new set of hi-hats, a new Midi control surface to replace my BCF2000, and a new Audio Interface to replace my Echo Layla 3G.
 
I am super excited about this because it was the perfect example of "found money".  Love it.  And while I went down this path because I'm likely to use two out of the three in Studio One, all three can be useful in either Studio One or CbB (which I am still attracted to).
 
Happy. Am. I.
 
I'll report back with the experience when I have all of these things - though maybe not in this thread! :)

Cool Blades.  I'm a sucker for a happy ending.