I just bought an iMic to use on a desktop system where I wanted to move the A/D out of the computer (builtin sound). I'm running Win2K sp3. It is easily recognized as an audio usb device and works without additional drivers. Under Win2K it only works as an audio capture device. No playback support. Under XP, apparently, both input and output work. I am just using it to transfer a lot of out of print vinyl to CD-R using as pure path as possible. I didn't want to spend very much on this so the iMic was attractive. My tests so far have been favorable. One hitch I have is I have to keep the input gain mixer slider at zero to keep from clipping. Not sure why the gain appears so hot. I'm using standard consumer level (e.g. 2 volt)inputs?
There are various posts on usenet where people have done some benchmarking on the iMic. Some have reservations but at $35 it's hard to complain. Some say it has the same or better chipset than the Edirol witch is twice the price. I'd be interested if you get the iMic to see if you have any issues with the gain.