I've installed maybe a dozen sets of McIntosh components (for customers, not for myself), but that was quite a few years ago. I always hoped they'd sound better than the last time, but they always left me hanging a little bit. I could never pinpoint exactly what my issue was with them, but they just seemed to color the sound more than what I was used to. For lack of a better description, they sounded very "baritone"- Like the lower midrange was peaky and the upper midrange was muffled. Female vocals (and Michael Jackson) just left me very unsatisfied.
I ran them off various amps in different installs, but usually McIntosh, a/d/s/, and Zapco amplifiers. Didn't matter if it was a 5.25" or 6.5", same issue with the sound.
I never ran them active, and it could be that their passive crossovers were the weak link- I don't know. I do remember customers being happy with their purchase but I couldn't get them to sound right to my personal liking out of the box.
I think at the time I was spoiled by a/d/s/ speakers, I almost never had a problem getting them to sound great. I remember swapping out the McIntosh separates in one system for a/d/s/ separates, and my frown turned into goosebumps when I played it again. The difference was drastic. That's probably part of why I still use a/d/s/.