Oooh that’s a tough one. I’m 6ft / 183cm exactly and on a large. Stock 50mm stem / 800mm bars. Best fitting bike I’ve ever owned but I wouldn’t want it any bigger if that makes any sense.
Super responsive, super snappy, climbs as good as my previous XC race bike, but I know a few people who are 5ft 10ish who find it a bit of a handful on steep techy climbs. Mike Levy’s Pinkbike review is a case in point as he’s 5ft 10″ and rode a large.
I’d say you could go both ways but as the previous poster said, you might need to shorten the stem on the large. Compare the geometry with your current bike to get an idea how it will ride.
Also, go for the X01 build if you can. The parts list upgrade is well worth the extra cost (plus it knocks around half a kg off an already light bike).