Easton all the way for me, every single bit of kit I've got of theirs is top notch, the Havoc Carbon bars are awesome and stupidly light for the width!
As a rule bars don't break, and when they do the warranty on your body is more important.
No way of getting any figures! How much do you weigh, how hard do you ride and what is the bike?
I know it's your money and you can do just as you please. But, why do you see carbon bars as an upgrade when you do not know what width you require?
Also what happened to the new group set you removed from your bike when you upgraded to xtr?