Slim - I don't have any aluminum frames, I'm not trying to play devil's advocate and I far prefer steel. I also agree about aluminum shattering vs. steel bending. The main issue for me is more about tubing diameter...I find most aluminum frames so oversized as to be VERY harsh.

I understand that the usage and rider will affect the fatigue life - and I'm sure not all aluminum frames are equal. A Kona might be more or less over built than a Cannondale. I'm still wondering if it's a relevant consideration though - I haven't heard of too many frames just snapping based on fatigue. Obviously wide spread aluminum use is fairly recent - early 80s on - so there is a limited sampling pool. That being said - I still see a LOT of 80s used Cannondales around and I haven't heard of frame snapping stories. Cannondale's life time warranty indicates that they thought it would be around long enough not to worry about fatigue life.

Ultimately, if aluminum frames were actually snapping due to fatigue, i think there would be more warnings and more data on actual incidents.