Cube Attain GTC Pro disc vs Giant Defy 1

Big dave 3

I would like some opinions on this:

http://www.rutlandcycling.com/320630/pr ... -grey.aspx

Currently reduced from 1500-1000. I would be using it as a winter/all year round bike. I currently have a Giant Defy 1 as a winter bike:

http://www.rutlandcycling.com/281112/pr ... iatewindow

Would the Cube be much of an upgrade? Also what size would I go for? I have a medium size defy that seems OK for me. I am 5' 10".