Your primary consideration should be shifter ergonomics. I have only played with SRAM Red 2012/13 shifters in a bike shop; no experience with them on a long ride. That said, I have owned a SRAM Rival groupset before; the SRAM Red 2012/13 shifters, which are similar in shape and function to SRAM Force 22 shifters, are more ergonomic IMHO.
Compared to Campagnolo 11-speed shifters, however, Campy still wins by a mile in ergonomics (I ditched the Rival in favor of Chorus 2013). If you've got small hands, you'll enjoy how Campy ergo shifters are shaped and operated. Then again, you have to try them for yourself. Not all are fans of the thumb shifters; as far as I am concerned, I'm a big fan of them.
Next would be gearing options. As far as I know, the largest Campy cassette only run up to 29t, as opposed to 32t for SRAM (if you're going for the WiFli option).
As for Ultegra 6800, I've laid my hands on a groupset in a local bike shop. Given that I've got small hands, I didn't enjoy playing with the 6800 shifters. While they're better ergonomically than the 6700 shifters, they're too big for me. Also, there's still that slop (that is, that "dead space" before shifting is engaged). If you don't like instantaneous shifting that may result in accidental up- or down-shifting, it may be a viable option for you.