The couple of modern carbon mountain bikes and several road bikes, over which I've thrown a leg, have convinced me that carbon is the way forward from the handling POV, they have all handled superbly well, absolutely amazing in fact.
However having seen my buddy's carbon frame after he and a car had a, er, coming together, a couple of weeks ago I'd be a bit reluctant to use a carbon frame off road because it is so vulnerable to damage. My own titanium Global is beaten up, scratched and generally well used but shows no sign of serious damage - it's taken several hefty smacks to the down tube from flying rocks, not to mention all the low speed falls, rock scrapes and tumbles that I suspect would have damaged a carbon frame.
In common with all Ti frames it is superbly smooth riding and rigid carbon forks and seat post do compliment it very well.
OTOH I don't rate aluminium for bike frames; I find it punishingly stiff.