I've been riding for more than 40 years, and this has to be the smoothest bike I have ever owned! The carbon frame is tuned very well for shock absorption, and the bumps that used to hurt are a distant memory!
Over the last 4 years, I've been racing a Guru Racelite, full DA, setup as a Tri-Bike. After much consideration, I added the Trek Madone 5.2 to my stable. And a second one for my wife.

I went with the Compact Ultegra Groupo for price considerations only.
The LBS sold me the 2012 Madone's at the same price as the 2011 Madone,'s since they wanted to get the first ones in Cincinnati.
Bought the Black Heli color, which is really cool, a mix of raw and shiny carbon. It's kind of cool to see the splotches of raw carbon, and then the glossy carbon on the top tube. Very cool! My wife thinks it's kind of ugly, and keeps trying to buff off the raw carbon splotches.
I've put 100 miles on it in the last week, and it has to be the smoothest bike I've ever ridden. The Ultegra Groupo is very smooth, the shifting is crisp, and the overall setup very good. This is the first compact groupo I've owned, but it performs very well.
The main change from the 2011 Madone 5.2 is the fork is now completely carbon, thru the headset to the top of the headset.
That said, do NOT buy this bike without purchasing the Torque Wrench from Trek ($20.99)! You will need it to adjust any of the bolts that touch carbon, as all of the bolts are the same size, and you don't want to send for frame in for repair! In addition, the headset needs at least one spacer above and below the neck.
The wheel set is OK, and I will probably upgrade in the future. As I am a big guy (6'5" and 225#) the handlebars are a little small in the drops, so a new bar is in my near future. My wife has the 44cm handlebars, which seem to work for her, but she has trouble with the reach to the brakes and shifters. The LBS gets a set of shims for the brakes, so if you have small hands make the LBS give them to you before you leave the shop.
My wife needed to replace the stem right off the bat, as it was a little long for her reach, and after 100 miles, I've had to move the seat a couple of clicks to make it comfortable for her. Otherwise, she is enjoying the Madone.
Have plans to do several 100 milers in the next month or two, and will report back on how the Madones are holding up.
