The missing piece of my collection is on the way from Canada. Couldn't find M150 from Finland, so bought it thru PF. Now I have all the M series primes from M28/2.8 to M*300/4. If LBA allows I'll skip the M400, M20 and M28/2, as I don't think I need them and too expensive to get just for single in challenge. I still have 2 months to shoot on my APSC round in the SIC before I can start shooting them in FF.
Some leftovers from M50/4 I'm using this month in SIC:
I've been impressed with this lens. It sure will be hard to pick a favorite fifty.