I was actually able to retain mostly the same keymap (I use a heavily customized Emacs/OS X/Eclipse keymap), so I didn't have to retrain my muscle memory much. IntelliJ's keybinding configuration is very flexible, and most of the features I like from Eclipse exist in IntelliJ, and it seems like everything has a keybinding. There was a few things that I couldn't get quite the same, but they were minor enough that I've adjusted (e.g. Emacs-style incremental search isn't quite the same -- it's just as effective, but the keystrokes/behavior for exiting out of it are different).