Sorry to hear the k-mix isn't working out... It looks like such a cool idea but if it's not precise and doesn't have visual indicators for things like a compressor that's a big problem in a mixer.
The one thing I haven't ever like about any of the mixer/audio interface devices is the quality of the converters... It never comes close to a dedicated interface (i.e. Apogee, Metric Helo, RME, MOTU etc). I've ended up using the built in (and really nice) software mixer in my Apogee interface for recording, and using a compact Souncraft mixer for live. I'd prefer to have one unified solution for workflow, but I don't want to sacrifice sound quality or recording flexibility.
My ideal would be a compact mixer with direct outs (pre/post switchable) so that I could use the mixer as a live device in the studio and on stage, while connecting it to a good quality dedicated audio interface for recording. Haven't found just the right one yet though.