The Good: incredible traction, tons of tire clearance, aggressive geometry,
The Bad: Not cheap, 4 x 4 suspension is not for everyone
Seems kind of silly these days to be writing a review for a 26" bike but if you're not in a hurry to switch over to larger wheels the Endorphin should be on your short list. I've been riding this frame for almost two years now and it is the best bike I've owned to date.
First off the geometry is dialed on this bike. Slack head angle (67*), steep effective seat angle (73.5*), low BB height (13.2-4" depending on tires), and short chainstays (16.7") working all together makes this bike a ripper. The numbers puts a rider right in the center and IN the bike for great cornering manners and aggressive handling.
The 4 x 4 suspension is not everyone, but if you favor traction over pedaling performance on flatter terrain you will love the Endorphin. Your legs will give out before the bike will when climbing. The traction is caterpillar-like over ledges and steep technical terrain. The 4 x 4 suspension also makes the bike's 140mm of travel feel like more and imo transcends the trail bike category. Point this bike downhill and you'll know what I mean.
The Endorphin has all the modern features that a good trailbike should have imo: removable ISCG-05, 12x142 rear, 44mm headtube, dropper post routing.The frame comes in at a fairly light 6.5lbs with fox ctd shock.When I purchased the bike almost two years ago, the fox ctd was the only shock offered and after I few rides I immediately replaced it with a Cane Creek Double Barrel Air. I felt that was when the bike truly hit its full potential. That was also before Avalanche offered their SSD mods for the fox ctd. I highly recommend either an Avy mod or DBair for this frame.
I really can't see improving this bike other than making it carbon. Right now you can find these for $500 or more off retail which makes it very competitive even with non-boutique frames. The suspension characteristics are not for everyone but for me it's exactly what I prefer and look for in an aggressive trail bike.