I picked up my new Specialized Roubaix SL2 last Wednesday. I put some long miles on one of these a few months back, and have a couple of good rides in on the new one, and I really think this bike is amazing.
I'm pretty critical of bike design, and over the years I've ridden an awful lot of good bikes. But this thing has completely re-set my standards.
For starters, it just feels fast. It's a cop-out to say that, without quantifying whether it actually is fast, but it's a fair and accurate summary.
The initial impressions I had were eerily similar to the first time I rode a full-suspension mountain bike -- my expectations of what riding should feel like were blown out of the water. Possibilities were expanded.
The most amazing characteristic of this bike is how ridiculously efficient it is, while still being superbly comfortable. The frame around the bottom bracket is huge, and the chainstays are very tall where they join the BB; likewise, the structure around the headtube is large and the junctions with the down tube and top tube are gigantic. All of this super-sizedness makes energy transmission from the rider to the wheels virtually lossless, and gives the front end stability that directly translates to more confident (and faster) descending.
More thoughts on what makes a good bike over at my other blog.