The Giant Defy Advanced and the Defy 1 or whatever are not remotely close to the same bike. Carbon versus aluminum. The entry Defy Advanced is around $1,500 with Tiagra.
Best bang for the buck is the CAAD10 if you like the ride. They make a bike over three grand on the same frame. The CAAD8 is ok, but for $200 more dollars get the 10. Totally different level of frame.