So, it's basically if you want:
- threaded headset / quill stem, a bit more old school style, cantilever rear dropouts -> (1992) / 1993 M2000/M1000/M700
- threadless headset, clamp stem, cantilever rear dropouts -> 1994 M700
- threadless, but no cantilever dropouts -> 1995 M2000/M900
The Beast of the East (M800) raised bottom bracket geometry is cool for technical stuff (saddle low riding), but if you want to ride non-technical trails (as most vintage users do) I would maybe steer away from those. For a tall rider it puts the center of gravity quite high, if you want to use all the inseam length for saddle height and efficiency.
The tig welded steel stems of some 1994/1995 bikes are not that awesome. The internal clamping surface is quite small and the thread material is thin, so easy to overtighten and ruin the threads. I think they changed to aluminium external clamp stems somewhere during 1995, even the catalogue photos are with steel stems.
The full rigid Killer V models with Pepperonis are also cool looking, and the reinforced frame is not bad for a bit larger rider.