I’ve ridden the new build a couple of times now, and compared to the Frankenstein Ultegra components I had on my bike, the Red is better in any way I can think of. When accelerating and climbing, I feel like I’m getting more power for less effort (a product of ceramic BB bearings as well as weight reduction in the crank & rear cogs).
The shifting is also great. Where Ultegra feels a little mushy, the Red is crisp and very precise. Doubletap took a little getting used to, but by the end of my 3.5 hour ride yesterday, it felt just as automatic as my previous shifting.
Last but not least, the brakes almost threw me off of my bike the first time I used them on the road. I adjusted them in as close as possible to my handlebars (very easy to do just by turning a bolt on the top of the lever assembly under the hood), and they’re very strong! The Red paint job on the levers is pretty sexy, too.

Check out pictures of the build a few posts down in the one titled “Red, white, and Blue” (yeah, cheesy, I know).