Before the conversation gets derailed, I'll just chime in: unless you're doing really hilly climbs, I'd go for the Madone. That being said, here are the knocks:
The brakes are a bear to set up. I built my bike up, myself, and this took longer than routing the cables through the frame (thank God for the liners!)
It is heavy. Like, really heavy. Like, heavier than my previous Madone 5 (all the parts that could be transferred, were transferred over from that frame - so it is an apples-to-apples comparison).
Here are the positives:
It is incredibly comfortable. Much more so than my Madone 5. I haven't tried a full century on it, but metrics are a walk in the park.
It turns heads, and you'll get a lot of questions - if you're into that.
Once you know what you're doing, the maintenance work isn't all that hard. There is a steep learning curve, however (it took me 12 hours to set it up, initially, but changing cables, recently, took me no longer than my Madone 5 (faster, actually).