OPENSTEP running on a MacBook Pro...

[SamuraiCrow]

WinUAE and the Intel Linux-based version of EUAE both support JIT-compilation.  The PowerPC-based versions of EUAE do not.  AFAIK the MacOSX version of EUAE is targeted toward the PowerPC Mac and therefore doesn't have JIT compilation.

The source code of EUAE is available at Rich Drummond's website (look for the download table at the very bottom).  Feel free to customize it to your needs.  I believe there is also a SourceForge project for EUAE that provides CVS support.

[SamuraiCrow]

JIT gets more speed on emulation so that the programs run as fast as the processor allows.  I've use EUAE on my MicroA1-c and even though it has an 800 MHz G3 it can't emulate an '020 at full speed.  My PC is an 800 MHz P3 and it does quite well on WinUAE despite being slower than my Micro.