The 2011 Felt DA is a great looking bike and it looks like the design is mechanical sound too. I'm hoping to build it up for the Life Time Fitness Triathlon this weekend. The changes I noticed from the past DA frame are the:
1. Seat post and seat post clamp - new shape and better clamp design. The post also has a battery mount for DI2.
2. Bayonet 3 fork and stem assembly
3. New frame shape - deep shape to the stays and lower stack height
4. New propriotery rear brake mount under the bottom bracket. It was previously mount on top of the chain stays behind the bottom bracket.