WHOOHOO, got my new bike yesterday, got all the computers on it this morning and took it for a ride on one of my normal courses to compare it to the older bike.
I went from a Trek 5200 with Rolf wheels and 8 speed to the new Trek Madone with Bontrager's and a 10-speed.
So far, based on some pretty good data to compare it with, I'd say the new bike has improved my mile times on flat ground by about 5-8 seconds, and in the climbs I do, about 10-12 seconds a mile.
The older bike was also a 58cm, and I went to a 56cm after a lot of debate and measuring, and I think it was the right move for me.
I'm using the stock, rock hard, and pitifullly small USPS seat on it for the time being. I had a really nice "man friendly" seat on the 5200. We'll see how my "manware" and back hold out with the new saddle.
Can't wait to ride some more. 🙂