I've had limited time to tinker, but it seems G5 support is not readly for primetime. My G5 is currently 2.0Ghz.

In Sysinfo:
E-UAE - 1.93 MIPS
E-UAE JIT - 2.65 MIPS
E-UAE.G5 - 17.27 MIPS
E-UAE.G5 SDL - 18.34 MIPS

E-UAE.G5 SDL is about 600% faster than current JIT on G5? Could that be right?