One thing nice about the FM2n is that you can still buy brand new focusing screens. I've got an E3 (grid) screen in mine; I'm not absolutely sure, but it seems to affect the meter slightly, about 1/3 of a stop. The E3, B3, and K3 screens were made for the FM3a but they will fit in any of the FM/FE bodies.

Overall I prefer the F2 to the FM2n, but the latter is still a lovely camera.