I have always run with JIT enabled in Froyo, and now in GB. It was 2.1 that is unstable with JIT, because (I believe) the actual Android code for 2.1 was not written to benefit from JIT.
There was a time when some popular apps (i.e., Pandora) would fail if you ran with JIT enabled, but I think that is long since fixed.
There was a time when some popular apps (i.e., Pandora) would fail if you ran with JIT enabled, but I think that is long since fixed.