This has been a topic in the hardware forum
…and the consensus there seems to favor RME if you can afford it. Personally, I use the RME Fireface UFX, which communicates by USB, or firewire in the alternative. I have 4 mic/instrument inputs, 8 line inputs, and additional ADAT/digital audio inputs that I’ve never used (and probably never will). It’s quite reliable and has low latency. I’m running at 3.515 ms input latency and 4.444 ms output latency (buffer size is 128 samples, sample rate 44.1 kHz). No errors, and 4 analog inputs at once, with some built-in compression and EQ active. I could push it farther. It goes down to 48 samples and up to 192 kHz, but I’ve never tried it.)
Needless to say, I’m very happy with it. Never had a problem. For a while, I used the fireface without a DAW, like a stand-alone mixer. I could have saved tracks to a connected HDD, but never did.
Some might say going with RME is overkill. I’ve not tried other interfaces, so I can’t say anything about them (good or bad). I knew RME was the best and I wanted quality, not unpleasant surprises. So I saved my pennies and bided my time.
If I have any concerns, it would be a lack of mic inputs, should I ever wish to record a group playing as a group. You can expand the fireface with an OctaMic II, say. But there goes another $1800. There are probably cheaper ways to add inputs.