I've only rode a friends bike that had SRAM Apex, the rest of my riding has been with Shimano products. At first I didn't like the funky double tap, but once I figured it out it wasn't a big deal. The gear changes are faster but feel somewhat clunky to me. All in all, if I loved the bike it wouldn't really matter to me if it was SRAM or Shimano.
Now the real question, what about Campy?