Many understate M&K's music performance. Yes, they designed for movies, which means they're not as good as a hi-fi speaker for music, but if you look at the M&K's that use the 5.5" drivers, they fare much better with music than the K's and Xenons. As an example, you could get something like the LCR750's, M4T's and a KX12 sub for a little over £1800. As far as I'm concerned, the best M&K's for music are the 750's and 150's. The first time I heard M&K for music I was quite surprised how good they sounded, and how much more detail I was hearing in electric guitars.
When setting up M&K's for music, they need far more tweaking than they would do for movies - getting the crossover point is essential in getting good music performance, but this can vary from room to room, so there's nothing set in stone.
Even though you are into movies and music, I would say it's going to be down to which one you want to sound better. If you want you movies to sound better then music, go with M&K. If you want better music than movies, look at something like the KEF iQ or the Dali Ikon.