Sure, 3.1 with a 4 or 16 color HiRes Workbench is fast. Noticeably faster than 256 color AGA, and 16-bit color via RTG. Still quite usable even with the 040 I used to have in this rig (now an 060.)
To be fair, my 030 500+ can still only do a 16 color Workbench, but even with that 3.9 is quite usable.
Sorry you had such problems. Maybe someone here can help before you put them back away -- either fix up your Amigas or take them off your hands.