As much as the CAAD 9 and 10 frames have such a cult following, I wouldn't recommend them unless you race. They are built as lean, tough, aggressive race frames, cheap enough to be replaced.
Now, I'm a CAAD fan, have been racing them since 2004 when I got a R800. I love them for racing and training, but they are not what I would consider a comfortable road bike, and not my pick for a century bike either. I ride a Surly Pacer for long rides.
of course, Cannondale doesn't exactly saturate the market with them, so perhaps my statement is simply to keep one more on the market.
i rode a friends Moots Vamoots a while back on a century. If I had to pick any frame to ride that would be it. That frame was everything. Comfortable, cornered well, BB was crazy stiff.
sadly I just cannot ever see me pre retirement ever spending that kind of money on a frame.