If your room has a lot of reflective surfaces like hardwood floors and is untreated, the M50's might be the better option because they are bit less revealing than the M22, otherwise I think the overwhelming opinion would be to go with the M22 as your mains and save some money in the process. Either speaker is suited and capable for your room size.

I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

-Max Payne