We had a bicycle demo at the local trail over the weekend, funny part was it was a Santa Cruz demo, not a Trek Demo. However, one of the other guys showed up to the event with his Trek Stache 9 (29er+) and let me ride it while he did a demo ride on a Santa Cruz Hightower 27.5+ bike. We rode a 10 mile loop, about an hours worth of riding.
The Stache was so much fun I am not seriously considering building up a Chinese 29+ hardtail for myself!
The Stache had the Bontrager Chupacabra tires that just gripped so well it was nothing short of inspiring. I could take any line, bumpy or smooth, through a turn and it just didn't matter, the tires soaked up the rocks and roots. The bike made the trail feel 50% smoother. On the flat stuff the bike also felt very smooth, the tires even hummed along like an off road truck tire does on the street. I've never "heard" my tires rolling along in the dirt on any other bike I've ridden. The tires were dialed in at 14psi and worked very well at that pressure. I'm sure if I added a bit more pressure it might feel different, maybe quieter.
The bike felt very maneuverable, not that much different than my 29er with 2.4" tires. To me, it rarely felt like I was on a bike with 29"x3.0" tires. I just felt like I was on a 29er that had tons of grip. Loose sand, no problem. Muddy spots, no problem. The tires never slipped. The only time you would feel anything is if you were turning just slightly at speed, that's when you feel a bit of angular momentum or gyroscopic effect from the bigger wheels. I'm sure a set of carbon wheels would decrease that a bit as well. The owner told me he weighed the Chupacabra tires and they were less than 900gr each. He also said they don't wear fast, 1700 miles and still looked like they had 50% remaining which is good since they are a $120 tire.
There were two faults I would post about this bike. One is the fork. I'm not a fork snob, to me as long as it soaks up bumps any fork is fine. However, the Manitou Magnum Pro fork was not very good. On big hits it was just jarring, it did fine on small to medium bumps but the larger hits or small drops is where this fork is lacking. If I were to build a bike, I would not choose this fork.
The second thing, and it's not really a fault, is the rear seat stays were wide enough that I could feel my calves lightly rubbing against them. I could also feel the seat stays when coasting, I would kind of rest my leg against them. It's not like my shoe heal was hitting the frame which would be a deal breaker. This wasn't too bothersome, I think it's something that I could easily live with, but it was worth noting.
The frame was a 20.5" (XL) and I thought it would feel big but it didn't, it felt similar to my 19" -057. The owner of the bike did say he changed out the stem to a 50mm one and put on carbon riser bars. I'm 5'-11" so it made me wonder why it did not feel like an even bigger bike. However, if you read the size chart on Trek's website, the Stache does have funny sizing. I may get the chance to ride a Large Stache 8 this Friday as another guy from a local bike shop said he would bring one up to the trail for me to try out.
After riding the Trek Stache 9, I rode the Santa Cruz HighTower 27.5+ bike. I was ready to give the bike back after just 10 min of riding. It just didn't have half the fun factor for me. However, the owner of the Trek Stache loved riding the HighTower and is seriously thinking of buying one. To each his own I guess.