I'm currently aware of the following Python JIT compilers: Psyco, PyPy and Unladen Swallow.
Basically, I'd like to ask for your personal experiences on the strengths and weaknesses of these compilers - and if there are any others worth looking into.
Thanks in advance,
Az
Some other tools you might investigate to speed up python are 

Cython, which requires type specification of all variables in the relevant method and then statically compiles the method
Numba, which requires LLVM but is JIT (methods must be decorated with argument types for compilation to occur).
Strengths and weaknesses of JIT compilers for Python