The only thing M&K has in common with Bose is that they both make speakers. As already said, the reason you don't hear much about M&K is because they rarely advertise in consumer media and are generally more focused towards the professional recording industry.
I just recently bought my M&K setup back in Late Novemeber and December. Actually I just picked up a second M&K MX350 subwoofer last week - my local dealer had a mint floor demo for $1250 which was too good to pass up. I currently run 3 S150's for L/C/R, and 4 SS150's for SL/SR/SBL/SBR along with the 2 MX350 subs for my THX Ultra 7.2 setup. I love it and wouldn't have anything else. For HT they are hard to beat and you'd probably have to spend alot more money to do so - as I'm sure you've heard M&K is practically the industry reference standard using by nearly every studio, Dolby, DTS, THX, etc. More movies and music are probably mastered on M&K systems than any other. Before buying my system I read a few posts indicating that they aren't as good for playing music but I have not found that to be the case. One of their strengths in accuracy and neutrality - they reproduce it the way it was recorded - and alot of people don't like to hear the defects in the recording and mastering process. Also, they are obviosuly satellite speakers intended for use with a sub and alot of stereo fans seem to prefer full range speakers so they find the satellites lacking in bass when used without a sub. Well duh....
Since getting my M&K's, I watch alot more TV and movies. I'm not sure if that's a good thing, but I'm addicted and have found myself rewatching movies I had already viewed using my previous HT sound system and have realized it's like watching the movie all over again - there's so much detail and sounds that I didn't hear with my previous system (which was decent). I can't say enough great things about M&K, and their customer service/tech support is top notch too.