I've been using MX as
my 365 project camera for more than 310 days now, so I think I'm able to bring a few conclusions about that camera.
What I've noticed about my MX is that 1/1000 speed isn't always exactly 1/1000, sometimes it is faster, but only on half of the frame. Said problem can be clearly seen
here.
I haven't experienced shutter problems on slower speeds, though, but before I started the project, shutter was working erratically - ranging from constant ~1/60 to constant ~1/1000. It usually returned to it's normal operation after 7-10 dry firings.
Another problem was MLU - camera would go into unofficial MLU mode, and stayed there. For the beginning, MLU "mode" activated only on 1/15 and slower, but eventually almost every exposure slower than 1/1000 was problematic. Since the beginning of the project, MLU went on less than a few times - when the temperature was well below -10°C and once when it was well over 35°C.
Drained batteries are so common, I don't even count it as a problem.
But, using Kodak S76 (SR77 equivalent) batteries solved the problem, I've been using the same pair for more than 6 months now. No-name LR44 batteries proved to be more problematic, though.
I can't say I've had problems with meter showing off reading, it proved to be more-or-less within film latitude. On the other hand, it's me who is metering brainlessly, like metering off the bright sky vs. building in a shade. But hey, at lease I've learned to think before pressing the shutter release.
Jussi, I say you've experienced just a little bit of possible problems with the MX, it could be worse.