zia, 2.5 years ago I bought my first roadbike - a LeMond Reno. It was perfect for me.

1 year ago, I got a Trek Madone. Same size, but radically different geometry. I was much faster at first, but it took about 6 months (and one professional fitting) before I felt as comfortable as on my Reno.

Cases in point: I could get "in the drops" to accelerate on the Reno, but the Madone requires a much more upright posture to accelerate. On a hill, standing was preferable on the Reno, but I'm much better off sitting on Madone.

You could have knocked me over with a feather when I figured all this out...but now that I have, all is well.