I've broken carbon and aluminum bars. The only difference is that the aluminum ones are cheaper to replace...
I'm pretty sure I'm going to end up with a Fizik Cyrano to keep things in the family.
If there was some definitive evidence that there was a comfort benefit to carbon,
I'd go with it for sure.
Plus, I'm pretty sure that my next bike will be a full carbon machine and will more likely than
not have an integrated seat mast so I won't be transferring the post to the new rig.