You know, with this much time you could just have tested it out yourself. Anyways... I have used them both and I say: definitely use wakaba, if you can. It has a better management panel, global postcount (cosmetics!) and some other little features.

A question for WAHa: I was curious, if you plan to develop Wakaba further? Because right now many sites are migrating to Trevorchan and it wouldn't be nice, if such a... hack became the definitive imageboard software.