I will post any differences.

Praxis ws my first choice but this came along at a pretty good price. Guess I got anxious...

Read about chain drop issue from 2011's... As campag points out there are many variables, but i hope 2012 took care of any chainring related situations.
I consider myself a strong amateur rider, and a bit ocd about durabilty/maintenance. Every time i sprint and get to the 11 tooth its important the chain stays put. Ive had situations, were my RD spits the 11 or the fd Throws the chain out! It a nasty feeling!