After using Shimano for like...ever....I built up my Trek 2500 race bike with SRAM. I like it. A lot. I now much prefer the SRAM bike over the Shimano bike. Took about a week to get accustomed to it, but I wouldn't trade it.
Get the Rival brifters and RD and save some cash. The only thing that is a noticeable difference between the two groups is the crankset.