For all intents and purposes the two groupsets are a wash; fanboys of either manufacturer will tell you that theirs is better but, in the end, the differences are so minute that any argument is pointless.
I went with Force22 on my most recent build. I know that the complete group is a few hundred grams lighter than 6800. The rear action is not as smooth as 6800, but this is more of a SRAM vs. Shimano thing. I like the positive feedback from the SRAM mechanism. The FD is awesome, it's much better than the previous SRAM offering. The built in chain catcher is great and the Yaw technology really does make a difference.
I love Double Tap. There is a learning curve to it but the reach adjust and dedicated brake levers really works for me. The hood shapes are also great. You need to try both and see which feels more comfortable in your hands.
You may hear some issues knocking SRAMs build quality. From what I've gathered and read, most of the issues are with Rival and Apex and older Red. You can read anecdotes of tuners who have taken apart Force22 and Red22 shifters and were pretty jazzed on the build quality.
When comparing and contrasting these two groupsets it comes down to ergonomics. Which hoods fit your hands better? Double tap or Shimano? Smooth rear shifting or positive feedback?
I, personally, will only ride SRAM. . . until I can afford Record