I got it installed and it’s awesome! The only hitch I had is that I forgot to backup my development databases on my iBook. Since there were production copies out there, it wasn’t too bad to solve that.
Zend Studio, which I love, wasn’t installing, but I managed to get around the installer crashing by installing 4.0.0 instead of 4.0.1. I don’t know why that would help, since I believe it’s an installer bug.