What are the differences between ClockworkMod and Team Win Recovery for the Nexus 7?
I'm partial to TWRP.  The biggest difference I've noticed is that CWM requires you to either boot into recovery or use Rom Manager to flash a rom, while TWRP allows any program with root access (goo manager, Rom Toolbox, etc) to flash roms.  There are probably some other differences, but this was the big one for me.