I have a 29+ bike equipped with 1 x 11 XT, have had it for a couple of years. I like the drivetrain so much I installed the same thing on my other mountain bike (a standard 29er), which had 3 x 10 XT on it. I've raced the 1 x 11, I've used it for my everyday mountain biking, and I've used it on the 29+ bike for bikepacking on both singletrack and hilly, dirt roads.
Through the years, I've used 7, 8, 9, and 10 speed triples on mountain bikes. All good stuff, but I'm hooked on this latest 11 speed Dynasys from Shimano in 1 x 11. I'm a fan of the simplicity of 1x, the positive feel of the shifting with the new cable pull ratio, the clutch RD, the 1x chainring that requires no chain retention device, etc. I'll use a couple of different chainring sizes, and both an 11 x 42 and 11 x 46 cassette, depending on the bike and the application.
The 1 x 11 offerings from SRAM are extremely good, too. We've sold a lot more of this in our shop, seems that most of the 1 x mountain bikes we've sold have been equipped with SRAM. I'm more a fan of Shimano drivetrains myself, but it's all good.
If 1 x isn't for you, that's okay, too. Having lots of choices is a good thing.
Last edited by well biked; 08-31-17 at 09:55 PM.