I just timed it, and IntelliJ 15.0.2 took 27 seconds to start up, load a project[1], and finish indexing it. The UI was visible after 17 seconds. As soon as they appeared, UI elements worked fine. I notice no delay or lag when ⌘ + tabbing to IntelliJ.

I'd like it if IntelliJ was faster, but I don't have many qualms with the current level of performance.

1. This project: https://github.com/Floobits/floobits-intellij