I got in a few miles on the new 5.2 last weekend. I really loved the bike. It feels stiff, it corners well, and the 56 seemed to fit me right out of the box.
I loved the bike, but I'm currently in the Campagnolo camp, and I really like being able to dump the chain...having said that, I really loved the Shimano brake hoods, so I'm thinking about converting back...