If you've ever played PvZ on the desktop then the mobile version seems to be pretty much identical in features. Only thing I can't find at the moment is the puzzles but that may be unlocked later.
I've been waiting for PvZ on Android for what seems like years. I can't stand how slow Popcap has been to adopt the Android platform.
iPhone PvZ players can correct me if I'm wrong, but I'm pretty sure there are several things missing from the desktop version (which I played a long time ago and for which I unlocked everything). I believe the biggest differences are the puzzle games. They're simplified compared to the desktop version. Also, there are no survival modes or whatever they called that place you grew plants in (did they call it the greenhouse? I can't remember).