Carbon can be laid up to be whatever you want. Soft, stiff, whatever. There is no limit to molding shapes and thickness variations. It isn't "soft" or flexy at the pedals and carbon will last indefinitely. It is worthy of it's price and reputation.

Kestrel makes great bikes. Not being in the pro peloton doesn't mean alot. Its just exposure. CERVELO is a perfect example of it. No one took them seriously until they entered the pro peloton. Does that mean they were not very good before? Litespeed sponsored Lotto/Domo but now they don't. Does that mean they aren't as good? It's all just advertising and politics.

Do research and test stuff out but what shows up in advertising and magazines just shows you who is spending the most on marketing. You miss guys like Parlee, Serotta, or Kestrel.
Test it out and if you like it, you should get it without worrying about who is riding what in the tour.