It's slow and buggy in my experience. I work on a fairly large Android project and over time it just keeps getting slower and slower. Doing things like closing/opening files of any size can take > 5 seconds even with a good SDD and processor, and this time increases as you use it until you restart eclipse. Also it crashes more often than any other IDE I've used and lately has refused to use emacs keybindings for me.
Lately I've switched using emacs w/ JDEE to edit code and Eclipse mostly just for debugging and the Android XML layout tools, which feels much better. I'm really interested in this new IDE from google, it'd be better if I could do all my editing/debugging in one program.