Wow Deb - thanks for all of this great info - I wasn't sure what I should be looking for with the frame material differences - this has been very helpful! I'm going to print it out and keep it in my jersey pocket!

It sounds like moving my current front wheel to each test bike would be a good thing to help isolate frame vs. wheel stiffness, right? I think moving the back wheel also would be too much of a pain.

Again thanks! I'll definitely report back.