I tested both before deciding on Shimano (6700). I didn't like how much force it took on Sram to shift from small to big chain ring and the noise made me worried I would snap the paddle. Shimano, this is the first generation that has under the tape routing so it seems to be a bit touchy with the housing and ferrule you use (need a metal not plastic one for reliable shifting). However I really liked the shape of the 6700 hoods with the kneck channel for your thumb and index finger. I also like the quiet smooth shifting. I prefer that Sram is rebuildable whereas Shimano is not but oh well.