Im with Brad on this one, or is that Mike?
Brads first statement suggested that the material used in the frame (talking steel only here) made little difference, but the geometry, sizing and joining was the true influence on ride. Mike disagreed, claiming that the gauge and butting of the tube has a huge effect. Am I quoting that correctly? If I am, then surely you are in agreement. The gauge and butting of the tube is its size not its material? Or am I missing something? I believe that the tubing gauges and butting that you can use maybe dictated to some degree by the steel you are using.
As to whether a stiffer bike is quicker or not, well I prefer mine with a little flex in them, although I dislike a race frame if I feel that the front end "bends" when sprinting. I find this feeling usually comes from the bar/ stem combination, although in my head I blame the frame. When I do get a set up that feels, to me, "Stiff" it usually ends up bouncing across the road at my pathetic attempts to ride hard and straight.
I have always believed that tyre choice and pressure has a greater effect than most things.
Regards
Martin Coopland