Hi,
I run PI 32 bit under OSX Lion, works fine, the only things that are negative are some graphic problems for example when dragging content the window does strange things...
Also i think there is a problem when you select "overwrite existing files" in the staralignment procedure, then it saves the files with a postfix but doesn't replace the original ones...
This is a bit annoying because you have to manually erase the original files...
Otherwise the 32bit one works fine and quick without itches.
Cheers
Lex