Test rode SRAM Rival for about an hour outside.
1. People are right that the front derailler has a pretty long pull (when on the hoods, more on this in a sec) in moving to the outer ring
2. Was very easy to pick up (but I did catch myself pushing on the brake sides a few times - shimano)
3. The absolute COOLEST thing in the world about SRAM double-tap is when you go into the drops, hug the shifters to the bar and can literally shift with just a flick of your wrist!
Without a doubt, the friggin' coolest thing in shifting in the last 5+ years.
You have to try that out. You pull the shifters against the drops and then you can shift with just slight sideways pressure of your wrist. It reminded me of what people say about the Segway - how it almost "knows" what oyu want to do by sensing minute changes in pressure. So FRIGGIN' cool.
(NOTE: Also, this was interesting, but when the shifters were against the bar in the drops, the long pull actually got shorter. I think this has something to do with the fact that SRAM's shifters don't really shift straight inward, but inward AND backward - so a backward angle)
4. I'd read that SRAM could take more pressure during shifts than Shimano. This wasn't my experience - it seemed pretty much the same to me. During some sprints, I tried putting a ton of pressure on the pedals while shifting both directions and it seemed to have the same catch problems at similar pressure to Shimano. (Of course, I didn't measure it with a power meter, so it was by feel)
5. I agree with people on this forum that the rear derailler is pretty much perfect, very smooth and precise, but the front derailler is OK. Didn't get a chance to test it with shimano FD, but it'd be cool if it was a tad smoother/more precise. Overall though, even the FD was pretty damn good.
6. While the FD has a long pull for the big ring, I did notice that it took less pressure to get it there than Shimano. I like this a LOT. Anyone know if this remains when using SRAM with shimano FD?
Overall, I love the double tap and first chance I get, I'm getting a set. I wish, though, that I could do more research into mixing of Shimano/sram, but I doubt any LBS' would build a test group up for me that way.