I have carbon aero bars, but would never put CF bars on a road bike. It's just one of those components where failure is not an option and bars get banged around and damaged very easily in crashes, etc. Since most of the bar is covered in tape anyway the little bit of bling and perceived comfort just aren't worth it to me. YMMV, of course.

And cost-wise, remember that just because it's expensive doesn't make it better. Most $30-40 alloy bars will be less likely to ever fail than a cheap $80 CF bar. You can get them for cheap, but if you want them built out of the nice stuff by a company that might actually cover some failures under warranty, the price tag goes up quite a bit.

It's probably the more paranoid view, but I like my collarbones a lot.