You won't get much negative talk about any CAAD in this thread. I am still riding my CAAD7 and it's a great bike. I don't know what model that is that you're looking at. It looks to be about a 2006 or so.
If you like it, buy it. There is a guy here selling a CAAD10 frame within your budget, but I'm not sure how much he would charge to ship accross the country. 2011 Cannondale CAAD 10 frameset