I'm shopping for my first road bike under $1,000 - $1,200, and while comparing Cannondale, Scott, Giant & Specialized as my top contenders I noticed that Diamondback with similar components are much less $$$... WHY?

Here an example:

For the price of a Giant Defy 2 @ $999 (TIAGRA):

http://farinas.com/product/12giant-defy-2-131090-1.htm

You could by a Diamondback Podium 2 '11 @ $599 (TIAGRA), or $759 for the '12 or upgrade to a Podium 3 @ $925 (W/105), still less than the Defy 2 w/Tiagra:

http://www.jensonusa.com/Diamondback...2-Road-Bike-11

http://www.jensonusa.com/Diamondback...2-Road-Bike-12

http://www.jensonusa.com/Diamondback...3-Road-Bike-12

Your thoughts? Could you help me compare other components? Is it for the frame or just marketing?

THANKS!