I own personally the Native Instruments Audio 2 (very small for portable use) and the MOTU Ultralite (exceptionally flexible and stunning EQ and effects suite). Also a very old M-Audio Fast Track Pro.
I'm also familiar with RME, Focusrite and Roland. Mates have their stuff. If I was to buy again from scratch I'd get RME. Not a lot of money for the best really but it looked at me at the time.
SQ is not a problem. I tested the MOTU when I first got it by comparing output direct from my phono pre-amp with a signal sent into the box (A/D) and out again (D/A). Neither I nor anyone I know could tell which was which. Very surprising. So I looped the output from one set of outputs backs into the inputs a total of 4 times. (The MOTU has 8 analogue ins and outs). Surely after 4 iterations of D/A > A/D I could hear a difference from the original? Nope. It's totally transparent, clean and flat. So is the very inexpensive NI. Same AK chip family as RME Fireface.
If you think about this it makes perfect sense. All the above companies businesses revolve around selling expensive DAW or similar software. Why would NI risk making Traktor sound bad? MOTU with Digital Performer? RME is genuine top of the range pro gear. Broadcast quality. They want customers to buy their software and sell hardware to make that easy and inexpensive. Annual s/w updates provides the jam.
It also has to be reliable and well supported. If your gear lets you down at a live recording session or something that's not good for bizz. At all.
The huge price and extra facilities pro gear provides is awesome. That's why I take the trouble to let others into the secret. It's too good to keep to myself.
That's not to say the more traditional hi fi grade suppliers are necessarily rip off merchants. It's more like the pro guys have been in the market longer (particularly the all important s/w side). Even the most expensive audiophile manufacturers are desperately playing catch up. Get it while you can.