Travis Northwaywrote a review of Niner Air 9 RDO Mountain Bike Frame - 2019 on June 3, 2019
Familiarity: I've used it once or twice and have initial impressions
Life has prevented me from getting lots of miles in on this bike, but so far I'm quite impressed. I have been pleased with how the bike handles, getting a few PR's on trails I've ridden a lot, despite getting out of shape over the winter. Bike weight with my "not a weight weenie" build is 18 lbs, 10 oz. Would not be hard to go sub 18 with this frame.
I'm real exited to get to know this bike over the summer, then throw some 27.5+ wheels to carry the fun through the fall/winter.