Asuming no abuse, carbon will outlast any of the materials, but it is vulnderable to cracking from impacts.
I can attest to the feel of steel. I only have one AL bike if that says anything
My Sedona actually let me finish a trail race after sustaining a 1.5 inch kink in one of the tubes! That was with rocks and climbs and all for 7miles. Did not even know until it was over. Then there is the other cool thing with steel, I fixed it. Welded a new tube in and now Im painting it up. Can't do that too well with the other materials.
That being said, Carbon has come a long way to being tough. As long as you are carful to look for deep pits and scratches it is good stuff.