I have a Focusrite 2i4 and it seems to work pretty well -- I A/Bed it with a Roland Quad Capture and, while the Roland has some more features, the recordings made with the Focusrite sounded just a bit more natural and detailed. Both sound better and cleaner than recording via the XLR inputs of a Zoom H4N. Knocks on the 2i4 -- for me, only two: metering could be more detailed than the green/orange/red LEDs it has and it seems to me that headroom on the 2i4's preamps is decent but not astounding -- I say "seems" because I don't have a ton of experience in this area, but check the specs relative to some other interfaces. I've fed it a healthy signal from Monique, though, without issues.
I had some some discussion with agedhorse, in a thread I put up awhile back, about recording at mic vs. line level with the 2i4 and my Genz GBE 1200. (
Unscientific Guess-the-Preamp Comparo: Demeter, Monique, Genz (with others later).) Scroll down a bit and you'll see specs for the interface and some clips. There are clips, throughout the thread, of a few different amps and pres and most were made with the 2i4.
In its price range, I think it's pretty good. Roland's not a bad option, either.