It's easy to get caught up in the comparative tensile-strength ratings of different alloys/tubesets, but these are strictly mechanical properties and have little affect on the overall strength of the built frame. The only thing that they really affect is weight, since higher strength steel can be made into thinner-walled tubing, but lightweight, thin-walled tubing, somewhat regardless of the mechanical properties of the material, is at a disadvatage when it comes to toughness and is more susceptible to denting and tearing. This is the reason why touring bikes, which need to carry a lot of extra weight, are built from fairly generic chro-mos like Reynolds 531 and 525, and not the high-tech 631 and 853 steels.