I tried out Eclipse on the mac for a couple of weeks recently but gave up on it fairly quickly. Not only was it slow (I was using it on a 1.5GHz powerbook G4, with phpEclipse, and some perl and python modules too) but after crashing it would never start again. I cleaned out the memory, I rebooted, but it just refused to fully open. So for now I’m using a mixture of XCode and SubEthaEdit for pretty much everything till I find an IDE which fits my needs better.