I've been trying out Basilisk II "Black Hammer Edition" and thought I'll try out both versions (non-JIT 'standard' and JIT-enabled). I have one hard disk HFV file with System 7.5.5 installed that I use for both versions of Basilisk II.
I've also been playing Escape Velocity: Override to see just how fast I can run the MacOS on my 1.47 GHz Athlon. Frankly, I'm amazed at the speed, especially disk access (I suppose the ATA133 helps). The startup extensions parade zips by so fast it's like they weren't there! It sure beats my Quadra 630, and it even shares my internet connection with WinXP using the NAT router.
First point: JIT seems a little slower than non-JIT. The extensions parade is definitely slower on startup with the JIT version (still very fast though, but not 'blink-of-an-eye' fast).
Second point: Also, something I noticed last night when playing EVO: I recently purchased a scout ship and practiced firing. I tried this on both JIT & non-JIT versions and my scoutship's guns definitely had approximately half the range when running the JIT version!
Obviously, I haven't done a more scientific analysis with a wider selection of test subjects, but unless I'm missing something somewhere, the JIT version was definitely giving me different results to the other. Clearly, if true, EVO is best played on the non-JIT version (I get longer range, which always helps).
One doesn't seem more crash prone than the other (although I haven't been using Basilisk for more than a few days), I have FPU emulation turned off (but I'm running Software FPU 3.03), and the screen size is set to 1024*768 @ 256 colours (I checked in the monitors control panel, just in case the different firing ranges were an optical illusion...).
Any thoughts? Sorry for the long post.