I run 27.5 with 2.6" tires. For me, and where/how I ride, they are the sweet spot.
I have, for some time, timed several representative climbs (I don't care about descent speeds) in the area, so my results aren't "feel", they are hard data. I do this, because I mostly ride with my son who is 39 years younger than me at 26, and I want to try to make the rides as fun for him as possible. So far so good. On previous climbs, on both a 26" and my 27.5, I found that 2.1/2.25" tires Vs. 2.25/2.4" tires was a faster combo. To get a smoother ride when I'm not riding all out, I got a 2.6" front and rear, at low pressure. Loe and behold, I have, on this combo achieved at least 3 personal bests this summer on my timed climbs and my son has commented on my strength this summer. Now, maybe it's something else, but I'm not inclined to go back to smaller tires! Ride what works for you. It may be a 29er - guys love them. But keep an open mind on other combos.
BTW, I'm in the airlines and was on a layover in Bozeman with a young first officer. We rented bikes - he got a 29er hardtail, which he prefers because he's a Strava/Leadville, etc. guy - I got a 2016 Trance with underinflated 2.4" Ardents front and back. At the end of a 1+ hour rocky, techy climb, I probably waited 6 or 7 minutes for him. I was pretty damned impressed with that bike! I don't know how the 2018 Trance rides, but the 2016 sure was nice.