I have an m-audio Profire 610 and it seems to work fine for me in Windows 8.1. m-audio doesn't seem to support it anymore and some people are having issues with Windows 8.1 (let alone Windows 10).
 
Most audio interfaces seem to be firewire or USB 2. If you were getting an interface today, which technology would you choose?
 
I am concerned about the age of firewire and how it seemed it was abandoned by Microsoft (again it seems to be working on my system).
 
Is USB 2 fast enough?
 
Thanks

From things I have read and seen USB2 is more than adequate for most applications. In fact, some AIs do not preform properly if plugged into a USB3 port (something to also be aware of).
 
Other things to check are specs and driver support. So many things by M-Audio "stopped" driver updates at Win7, so I jumped ship when I began replacing hardware. Spec differences will more often be trivial in comparison to the maturity of the drivers.

USB 2 is fine, although USB 3 is now becoming commonplace.  USB 3 is far faster than anyone needs right now, yet is still backwards compatible w/ 2 for the most part (check first).  Firewire is still viable through pci cards, which means desktop.  It is more efficient than USB, but again, it is fast enough for all practical purposes.  If you need 32 channels at once you need to go to MADI or Dante.
 
What I'd get is Burl for ADDA, but that is tré  expensive (about $6000 for a 4 X 8 configuration, their smallest and you still have to get that sweet sound into your computer so save another $1000 or 3).  The best buy right now is the TASCAM uh7000 for my money.  $400 for a 2 X 2 USB 2 interface.  Top of the line conversion and preamps.  Latency can be a problem, but it also uses spdif or AES digital, so you can plug it into many other interfaces that have those connections.  Most of the lower-priced interfaces are about the same sound and spec wise - you just need to make sure it works on your system.  Even RME, considered to write the best drivers for both latency and stability (neat trick that) can have problems with any particular PC system.  Every driver can have a problem, so it is best to buy one you can return and get one that does work.  Focusrite is a favorite here, with TASCAM (the new hardware company associated w/ Cakewalk since Gibson own both) making waves with their newer line of USB interfaces (the uh7000 was a bit earlier tho the preamps share the same topology, I believe).   And they are cheap, starting at $150 for stereo and only twice that for the 16 X 8 unit.

I have an RME UFX and even though it can use USB2 as well, I prefer leaving it connected to FireWire 400. My Studio DAW has a PCIe FireWire card and my HP Laptop has an Express Card slot with a Firewire 400 card in it.

I much prefer firewire.... and it lives on through Thunderbolt, if I were to get another interface it would be thunderbolt2. However with recent MS employee comments about Thunderbolt and Windows 10 that makes me want to think again, does not seem a priority for them.
 
There are apparently USB3 interfaces out there, if you buy one though buyer beware, often the manufacturer tends to imply they have all the benefits of USB3, yet they actually are just USB3 compatible and have the bandwidth of USB2.

Oh and ps....
 
If I were to get a USB interface I would strongly consider buying a dedicated USB adapter card for it.

my old pci card is rock solid.
 

USB2 is plenty fast enough and you'd probably not notice any difference at all between USB2 and Firewire, nor between USB2 and USB3. If you're worried about potential obsolescence, get one of the newer units that have both USB and FW. I prefer Firewire because it's a bit more CPU-efficient. But either one will move the data just fine.
 
An interface that's connected directly to the PCIe bus will always be the champ for efficiency. I just prefer the interface to be outside the computer - fewer cables and mess behind the computer that way.

In another thread, someone suggested (if I understood correctly) that RME, Lynx and MOTU tend to have lower latency systems. RME is more than I want to spend and Lynx looks like they just sell cards? I don't want a card. I like my external m-audio device. That leaves Motu and they just happen to support both FW and USB. Albeit they are not cheap but at least I can get something < $500.
 
Hopefully my Profire 610 will just work in Windows 10 but since it is no longer supported I can't guarantee it. I am researching now so that the day I install Windows 10 and find that the interface no longer works, I need to get another one ASAP.
 
I really like the price of the Focusrite stuff but I think I need 3 pairs of analog outputs. I connect my interface to my monitor speakers, PA (for jam alongs) and recently had to loop a set of outputs back to the inputs to accomplish a task.
 
Thanks for all the input!

Lynx makes both converters and interface pci cards.  8 or 16 channel ADDA which work nicely with a USB card in their slot (according to reputation).  They also have pci cards w/ AES in and out (those work w/ their converters, too, which come w/ AES plus the slot).  They also have an upper end combo interface, as well as new pci cards w/ even better ADDA (so they say - their earlier model was completely professional and up there with most no-boutique models).  2 or 4 channels plus 2 or 4 digital channels for about a grand.