I love 29+. Not just because my Chupacabra+curved blade rigid fork is the smoothest ride short of suspension I've ever had (and allowed me to ride rigid again for the first time in years) but also because:
-Great way for really big/tall folks to get on a tire that is proportional in diameter/volume to the loads they're going to put on it.
-3" tires are a great in-between spot for folks who don't want to ride a full-on fatbike OR race and suffer on 2" semislicks.
-Traction is just outstanding (I like around 15-20psi) and it's hard to go back to skinny tires!
-They are a no-brainer for tandems where traction, rollover, and stoker comfort are big concerns.
Here's Tom's fork intimidating a 2.35" tire that was an innocent bystander.