Migration to python 3 was not too bad, but wasn't easy either. I found the
python3porting.com page very useful:
https://sourceforge.net/p/forge/documentation/Project%20Web%20Services/, together with the 2to3.py script, then I replaced all code that 2to3.py changed with a utility method from a new py2and3.py module which selects the right method based on python version. No noticeable effect on speed, I was a little surprised. Python 3.2 and 3.3 all tests pass. Only one error in 3.4.
Oliver