Andrew R Stewart 

I can't speak to the specifics of either material but here's some well agreed on generalizations.

Pretty much all steels have the same Young's Modulus (stiffness). Some stainless can vary from this but not by much. Steels used on a bicycle are a balance between strength and brittleness. Too much strength and the steel tends to have too little elongation. Elongation is a needed quality to a structure which sees many (hundreds of thousands) of cycles of stress/flexing and not fail. Corrosion resistance- coating with paint and periodic maintenance do a pretty good job already. Brazing temps- here there is a change which will effect the builder. What type of joining techniques are available to the builder and how these choices requires the builder to use certain joint set up methods is a real factor.

An example of this is well known with 753 Reynolds tubing which wasn't meant to be bronze brazed (due to the temp level changing the heat treatment). So to join tab type drop outs to stays/blades with silver a plug or some insert was needed to reduce the gaps to a size silver could work with.

Another example of a tube's having a lot of strength is the maintaining alignment during the brazing process. Heat distorts the frame members as we all know. The builder must take into consideration how much and where this distortion happens and set up the tubing to accommodate this as well as use a building sequence which minimizes this. After a frame is completed a too strong steel won't be able to be cold set. Aermet tubing had this issue.

I'll be interested in reading more from better informed posters. Andy.