Would you buy a Firewire or USB 2.0 interfaces TODAY!?
The time has come to replace my Digi002 which has served me good for the last 10 years!
I really would like the buy the RME UFX interface, but I'm afraid that I would be buying an outdated item! Firewire is out in favor of Thunderbolt and USB 3.0 is all the rave, even RME has announced it's first USB 3.0 interface...
Should I hold my horses? How long will it be until the UFX gets an USB 3.0 update?
RME have a USB product already, the RME UCX (its gor both FW and USB2)...
In terms of a USB3 interface, do not bother waiting. The bandwidth requirements for audio processing is not particularly huge. USB2.0 has no problem handling multiple recording streams and audio paths over USB2. Going USB3 is simply overkill. You will never need the extra bandwidth and it would make no difference.
There is a reason why most manufacturers are still using USB2 instead of USB3 these days. The extra USB3 bandwidth is not required and it allows the manufacturer to save costs and produce an item for less, which means a cheaper price tag for you at the till.
Eventually as USB2 is universally phased out (which is already happening) completely that USB3 will be the same cost as USB2 is now that the manufacturers will have to incorporate it...as no one will be making USB2 components anymore! But until USB2 components are no longer being made, you will see USB2 interfaces before USB3.
Unless a manufacturer uses the USB3 as a marketing ploy....but expect to see higher price tags as a result.
That applies to USB2 vs USB3...
FireWire (FW) is a different protocol that is faster than USB2 and more importantly, it is far more reliable than the USB protocol. While on paper it is much better than the USB protocol, lack of universal uptake on the FW protocol meant that USB won the "war" and FW is on the way out. Thunderbolt is its replacement (of sorts), though TB itself is a bit of a niche product.
I personally also had the chance to move away from FW at no cost to myself recently so I took it. I said goodbye to my MR816X (great unit) and got a Focusrite 18i20 instead. Its also a great unit and does me fine for now. Most of the "higher-end" units are still FW, though as you said, most of the manufacturers are only now moving away from FW.