When I went to laptop as primary DAW I decided to the jump which meant shelling out for new primary (so far only, a USB2) audio interface. Purchased the Scarlett 18i20 2nd gen.

Laptop has thunderbolt and USB2s.

But my desktop HP is getting a few years on it. The FireWire is rock steady, after the proper chipset I/o was added no problems.

That did leave me with extra M-Audio FireWire 410 and Edirol FA-101.
I still use the 101 though, until I change desktops.

Not the same problem, but I bought an MOTU 896Mk3 Hybrid which has USB 2.0 and Firewire interfaces.  I was using it with my old PC that had both USB 2.0 and 3.0 ports.  It won't work reliably on a USB 3.0 port but fortunately I had a USB 2.0 port.  I built a new PC that has a USB 2.0 port internally on the motherboard but it was being used by an internal device so I only had USB 3.0 ports.  I bought a PCIe firewire card (T.I. chipset) and now using the 896Mk3 Hybrid on Firewire.  There is no loss either way, I get the same low latency whether USB 2.0 or Firewire.
 
 

Yep that was the hardest part. I had good latency in firewire rig. What made change is the desire to increase my I/Os. From there I had to decide in my mind......to go with one or the other for the next step.

I sold my M-Audio 1814 about 6 years ago, which was a constant pain in the _______ onI have the USB Roland quad two different laptops both with Firewire TI chipsets.
 
I have the Roland Quad, and it's been pretty much problem free. I've had to delete the Aud.ini file from time to time, but over 6 years, nothing of concern. I wish it had a separate Headphone and main out level controls, but that's more an issue with the unit than with USB 

Review some of Jim Roseberry's post... usb2 carry's NO latency penalty... you just have to choose your interface carefully...  heck, RME has among the LOWEST latencies documented and this is with USB 1...for heavy projects, USB2 is fine but again, it's the quality of the interface that will dictate latency.  Jim's published a LOT of this info right here in the studio section if you do a bit of searching.

Got rid of Presonus Firepod (The old one!) Firewire and moved to Behringer XR-18 USB 2.0 interface.  It works fine, gives me 18 channels simultaneous input and LOTS of routing options.  It can also be used as a digital mixer (while recording the 18 channels!).
 
I know Behringer is not known for its quality, but lately they have been stepping up their game.  With the acquisition of MIDAS, they use Midas designed preamps on this and they sound good to me.

patm300e
I know Behringer is not known for its quality, but lately they have been stepping up their game.  With the acquisition of MIDAS, they use Midas designed preamps on this and they sound good to me.

Nothing to complain about the latest Behringer desks. X32 is a killer tool for what it costs. Perfectly reliable live workhorse, but since for efficiency they limited it to 44/48khz, I don't use it in the studio ...

 

Rob[atSound-Rehab]
Nothing to complain about the latest Behringer desks. X32 is a killer tool for what it costs. Perfectly reliable live workhorse, but since for efficiency they limited it to 44/48khz, I don't use it in the studio ...

I set mine to 48K good enough for me...Been recording there for years even with my FirePod which COULD do 96K.  I tried 96K and 88K and really could not hear any difference, but I could see it in the file size!  96K and 88K files were much bigger than 48K.
 
 Then there is this thought process:
https://en.wikipedia.org/wiki/Sampling_(signal_processing)#Sampling_rate
 
I do use 24 bit depth...
 
At any rate I am not a "pro", just a hobbyist...So I have to pay to play and I don't get paid to play...
 

When my old Presonus interface dies I'll probably go the usb route. I don't have an intensive need for a lot of I/O. Any clients will send me tracks already recorded.
 
I can't say enough about how stable and dependable my firewire setup has been. To change it is going to be like saying goodbye to an old friend. I like the fact that my usb buss is separate from my recording bus. All of my other peripherals , my keyboard, mouse, usb 3.0 sdd are on their own connections.
 
I have zero interest in Thunderbolt at the moment. Neither one is bad or good, just different. 
 
If I were looking to track a lots of inputs. I would probably steer away from usb 2.0. But that's me.

Even though I use USB for Keyboard & Mouse (I actually have Keyboard mouse and monitor through a KVR switch!), I
have not had a single USB issue with my set up.  This includes using one USB back up drive as well in addition to plugging in various sticks and drives.