How many of you out there are using a Red crank, how does it compare to Shimano? Not trying to start a debate as I know Shimano has some of the best cranks in the business.

I can either go Ultegra 6700 or Red with my new build. RBR has a bunch of being saying the Red crank is flexy (I'm weak, if those tdf riders can use it, i'm sure it's not going to flex with me).

Also, have there been different versions of the crank, and if so, how can you tell?