I've had steel, ti and carbon frames break, and I'm only 140 lbs. There is no bike frame material that is 100% secure against breakage, at least not in a weight that people are willing to buy. OTOH I have had friends ride and race on the same carbon frame for 10 years before it finally died.

You can get Ti frames for much cheaper than a $5500 Moots. Habanero is a good outfit that's been around for a while.

Whatever you get, make sure there's a decent warranty that the company will stand behind, and the company is sound enough to be there in three or five years when you need it.