I remember when I had both the M3's and M22's. I thought overall the M22's were better speakers (and perhaps some of the best bookshelves I have ever heard), but the M3's had a certain sweet sound.
Having never heard M50's, I can't comment on those, but yeah, my M80's are definitely well worth having over M3's or M22's, provided you have a strong amp and decent space to put them in. I tried the M80's in a small room once (12 x 10 I think), and they didn't sound quite right. A tad thin, and no imaging. You need something bigger to take advantage of them.
