I have about 1K miles on my first SRAM driveset - 1x11 on a Jamis Renegade - and my first KMC chain. A testing article had the KMC chain rated worse in friction (more power loss) until KMC recommended NFS oil. Kind of expensive, but they claim you use less and I like trying out stuff like that.
I'm very impressed with the SRAM Force1 groupset. Not sure I can really tell the difference with the chain and only 1,000 miles is not enough for any kind of endurance/reliability testing. I have a chain wear indicator tool - not showing any wear yet. On my Trek road bike with Shimano chain, I usually get 3-4K miles before hitting the recommended replacement point.