While selecting components for my new build I had narrowed the group set selection to either Red or Dura-Ace. Both group sets do everything well, so for me the determining factor in selecting Red was the new brake lever design and the reduced finger force required for braking - nice on long descents.
SRAM did some really nice things (tools, indicators) to make installation so much easier and make the setup go smoothly.
The other thing I will comment on is the Karoo. Having used a Garmin Edge for years I was predisposed to not like the Karoo. But it didn't take long for me to end up preferring the Karoo. It's intuitive, integrates well with the group set, easy to install routes and just has a nicer display (compared to my Edge 840).
