I've been a big fan of IDEA since I made the switch about two years ago ... but as I've run each new preview release of IDEA it seems to be getting slower and slower. My Tapestry integration tests take about 5 to 6 minutes to run from the command line; inside IDEA the time to run has recently spiked up: they are now taking 15 - 20 minutes ... I just had a run take nearly 30! My suspicion is that it has something to do with all the console output from the tests. I see the launched Java process (which runs TestNG, Selenium and Jetty) consuming 3% of CPU and IDEA consuming 97%. IDEA is almost completely non-responsive while the tests run. I run both IDEA and the launched Java process with 600M max heap.
Two years ago, IDEA was stable and Eclipse was not runnable on Mac OS X. That's what prompted my first switch to IDEA. I'm now finding Eclipse to run faster on OS X and on Ubuntu. Lately, I feel pulled in the opposite direction: IDEA is quickly becoming too painful to use!