I'm personally not in love with Focusrites Mix Control software. 
I'm finding it a bit buggy. I have also noticed the meters are always showing peaks that I don't believe actually happened. It has a peak hold and almost everytime I open the mixer both inputs and output have the red indicator stuck there. 
I don't buy it. I'm working on projects that are well within the saftey zone and Sonars Master bus is not showing a peak. 
While tracking I'm finding I have to record a bit lower than I did with my Tascam as those red lights bother me. But same story, they certainly don't match Sonars track meters. 
 
I wish there was a way to not have to use the mixer and go directly. The Mix Control looks like it will be useful when tracking a full band, but for one person it is not needed. 
 
And I would rather use a real mixing board anyhow. If I ever build a bigger system I'll go with a digital desk and some sort of MADI or ADAT to PC. 

I've been very happy with my Focusrite Scarlett 18i20. Great sounding preamps and rock-solid driver's. I haven't got into mix control yet so I can't comment on that but I think for all the features it offers it's the best interface out there in the $500 price range. Seriously there's a lot of I/0 and the option to add more if/when needed. 
 
 

The Focusrite Scarlett 18i20 does NOT have built-in DSP for 'zero-latency', i.e. live monitoring.  They give you some plug-ins for effects, but the signal must go thru the DAW.  I wish this weren't so.  I would buy one and dump my Presonus 1818VSL in a heartbeat if the 18i20 had effects in the Mix Control software.

wruess
...dump my Presonus 1818VSL in a heartbeat if the 18i20 had effects in the Mix Control software.

Why? What are your experiences with the 1818VSL? How do you use it?

wruess
The Focusrite Scarlett 18i20 does NOT have built-in DSP for 'zero-latency', i.e. live monitoring.  They give you some plug-ins for effects, but the signal must go thru the DAW.  I wish this weren't so.  I would buy one and dump my Presonus 1818VSL in a heartbeat if the 18i20 had effects in the Mix Control software.

I am confused by this comment, but also never used the Scarlett line. I thought the MixControl software was similar between the two. My Saffire 24 Pro DSP has compression/EQ (for inputs) and a reverb bus that can be mixed right in the box and sent to direct monitoring (or even recorded). My uses are pretty simplistic, but that comment makes me wonder if there is a difference between the Scarlett and Saffire versions. I often see them used interchangeably, so now I am a bit confused.
 
The best overview video I have seen for the MixControl software is this one.

QuadCore
Hi Sonar X peeps.  I have my eye on a MOTU 828x (to be connected via USB to PC win7 i7) because it has virtual live mixer for latency free overdubs, the processing looks to be decent, and it has more than one S/PDIF I/O (RCA & Optical), but i don't know enough about the Virtual live mixer and effects to make a decision.  I am also considering the RME UCX for its virtual liver mixer and effects, and for its more than one S/PDIF I/O (RCA & Optical), and although it cost a lot more, the RME virtual mixer looks pretty versatile.  There is a lot to consider, so i thought it's time to see what other people have to say. 
 
So i'm very curious - what do you all think is the best audio interface to work seamlessly with Sonar X3 (and win7 64bit) and beyond?

 
You may want to check out TC's Impact Twin. The built in DSP reverb sounds great and IS NOT printed to the track when you record. However, the eq and compressor will be printed if you use those 2 efx. The conversion of this unit is outstanding and compares and or wins out against higher price point interfaces. It's a gem.

jfyi the Motu does NOT print Reverb, too, but eq/dyn on input always.

thomasabarnes

TabSel

I want to stress this issue to the OP, and to anyone who considers buying the motu for zero lat monitoring with DSP fx: it then Is NOT possible to record dry.
 

 
In post #16 I explained a possible way to do that, but it must not be what you mean you want to do.
 
After pondering to understand what you are trying to tell us, it looks like what you're trying to convey to everybody is "it is not possible to apply an effect to an input signal using CueMix FX and get a dry recording when you record that input."
 
If that's what you are trying to say, you are right. If you apply EQ and compression to the input signal, you will record the processed version of the signal in your host audio software running on the computer."
 
But "input signals to the computer can be recorded wet, dry, or dry with a wet signal" using the MOTU 828x as the only audio interface. I explained how to do that in post #13. I wonder why you still can't see it. I'm thinking maybe English is not your native language, so we're misunderstanding each other, or I've done a poor job explaining. Whatever the case, the OP said he was considering getting a Fireface UCX. I would say: "get the best audio interface you can afford," and I'm sure most would agree that the Fireface UCX is the better audio interface.
 
Cya all around

While I agree that TabSel's original review of the 828 seemed very harsh and unfair, I actually agree with him on this point and I think it's very relevant to the OP. If you want to record dry but have your interface provide some FX (eg for vocals) you cannot do this properly with the MOTU. You can apply a bunch of FX to an output pair but that is not the same thing. You would be putting the same reverb, eq and compression on the entire mix going to that output. What you want to do is craft a nice vocal sound using the provided tools (compression, EQ and verb) and then add the backing track separately while recording dry. This seems to me entirely expected behavior of a recording interface with DSP fx. Even my aging and limited E-MU 1820M does this. As does the super simple 0404. I definitely think this is worth noting to the OP.

If the OP has the budget, an RME audio interface would be a great choice.
Think of RME as the Neuman of audio interfaces.
Rock solid, great sound, and they'll last 10+ years.
 
MOTU is still a good choice.
I used a 896HD for the better part of a decade.  Also used an 8-Pre quite a bit...
Both were rock-solid... and sound was pretty good (slight notch down from the Fireface 800).
Lots of folks slag the onboard preamps... but I've captured some pretty good sounding acoustic drum tracks using them.
 
Lynx is another solid choice.
The Lynx units can be a little more finicky than RME.
ie:  Their older PCI cards don't cope well in bridged PCI slots.
 
On the lower cost side, I like the new UR-44 from Steinberg... as well as the newer Presonus VSL series.
 
My recent experience:
Having used the 896HD for many years, it was time I upgraded the audio interface for my main studio DAW.
I was very close to getting the RME Fireface UFX... but I wanted to checkout some new digital mixers.
Our live sound guy was using a Behringer X32 digital console... so I decided to research its use as an audio interface and studio mixer.
 
The X32 comes with a built-in audio interface (either Firewire or USB)... but there was no solid information about its round-trip latency and the performance of the drivers.  Behringer certainly aren't known for producing top-notch USB or Firewire audio interface drivers (that yield glitch-free audio under substantial loads)... but the unit has an AES-50 port that streams 32 channels of I/O via a single CAT5e cable.
I was hoping the onboard audio interface offered round-trip latency in the 5-6ms range (which is what I'm comfortable with via the 896HD).  Worst case scenario, I'd grab a Lynx AES-16e-50 audio interface (AES-16e with an AES-50 port).  After extensive testing, the X32's onboard audio interface essentially "requires" round-trip latency ~10ms to be 100% reliable (glitch-free).  The unit's driver was extremely flexible in that you could tweak both the ASIO buffer size and the "safety buffer".  I could set the round-trip latency much lower than 10ms... but there were dropped samples (especially when looping) when running heavy loads.  I didn't want to take a step backward in regards to round-trip latency... so I opted to get the AES-16e-50.  
Note that the Lynx AES-16e-50 is currently the only audio interface with an AES-50 port.  I had used the AES-16e before (as well as numerous clients), so I was confident it would work.  Got the unit installed and can run heavy loads (glitch-free) at the 32-sample ASIO buffer size (with double safety buffer enabled).  That's round-trip latency of 2.3ms.  Add the end-to-end latency of the X32 (0.8ms) and you have a total round-trip latency of 3.1ms (at 44.1k).  That's awesome performance.
 
I measured the average noise-floor at -114dB... which bests most audio interfaces.
That's just a smidge higher than the UFX which is ~-117dB.
 
While certainly not an inexpensive solution, the combination X32 and Lynx AES-16e-50 is extremely powerful and flexible.  Downside:  The unit is currently limited to 44.1k/48k.
I'm ok with that limitation...
When we do production for local and national radio spots, we're sending 44.1k wav files.
 
 
 
 
 

I haven't run very heavy loads yet but the music school I work at has an X32 and it has been trouble free at like 3ms latency (according to the settings menu). What sort of things caused you problems specifically?