The M3-220 is certainly unique if nothing else. It's basically a 2.1 system on steroids, with fully active 2-way satellites. Much better than your average PC sound system for sure. Still, it's a 20-year-old design now, and by the looks of it the sub is bandpass so more geared towards output than highest quality, and it's not like you couldn't get a decent pair of 5"-8" monitors for the 415€ it costs - but you probably wouldn't consider the M3-220 if you could spare that kind of space, right? People do mostly seem to like it, with just a few complaints about audible mains transformer hum from the sub (hiss wise, one review says it's audible 30 cm from the satellites, so nothing too excessive). Also make sure that the stock satellite cable length (about 1.5 m from sub to sats) is sufficient or else order longer cables. Support is supposedly very good.
If you want the UMC22 just for having (impedance-)balanced outputs - don't. Get an adapter cable to use your existing onboard sound instead, which has far more modern converters with better performance. The M3-220 features a 2-prong power plug, so unless you motherboard has some internal grounding issues there shouldn't be any problems with external ground loops. (If you can plug headphones into the back and start Furmark and hear nothing, then I wouldn't be overly worried.)
The appeal of the UMC22 is having an integrated USB recording solution (complete with phantom-powered mic input) for an unbeatable price. If I had decent-quality existing onboard audio not mucked up by the board manufacturer, I would strongly consider plugging a little mixer like the Xenyx 802 (plus 2x TS to 3.5 mm cable) into that instead, and use ASIO4All if need be.