As thegoose said,battery damage is the number 1 concern.
Look for motherboard revision 9.2 or 9.3 these are very good/stable. Buster 11 may be a plus,but 9 is workable.revision 7 boards usually had the rom towers and avoid them if possible(theres nothing wrong with them,and the rom tower can be gotten around,but i would go for later boards).some earlier boards had the scsi termination power diodes backwards also.Plenty of zip ram is a plus also,since the zip memory is expensive.High density drive is nice,but again not really a must have.
Dmac 4,ramsey7 chips are a plus,but dmac2/ramsey 4 is ok in most cases.Most of these chips are socketed so buster 11 can be changed, dmac4 is hard to find these days.
Avoid any boards older than rev 7 imho,and also avoid 16mhz machines.
hope that helps.
Mike
