would it be safe to say that in terms of failure rate, ti is probably the longest lasting when compared to carbon, aluminium, steel?
doubt there are proper statistics on such things as it would depend on manufacturer and how well they keep records etc
In my limited experience I'd say that steel was probably the best in terms of failure rate, but at the price of a bit of weight. I don't personally think that aluminium is a very good material for bikes - I've had two aluminium frames fail on me through work hardening / stress fatigue - type fractures, and I wouldn't buy another one. Plus it's not at all comfortable on a longer ride.
In my limited experience I'd say that steel was probably the best in terms of failure rate, but at the price of a bit of weight. I don't personally think that aluminium is a very good material for bikes - I've had two aluminium frames fail on me through work hardening / stress fatigue - type fractures, and I wouldn't buy another one. Plus it's not at all comfortable on a longer ride.