I picked up this Krampus 29+ from a local bike shop (e-bike shop, to be exact) employee who built it up with 9-speed Sram stuff. I pretty quickly swapped it to 10-speed Shimano XT and Zee components. It also had a beefy MRP chainguide on it (the kind that mounts on the bottom bracket shell) that I thought was really ugly. I mean, it just ruined the whole aesthetic of the 1x drive train. Long story short, in order to ditch the chain guide, I had to get a rear derailleur with a clutch mechanism (and nobody makes a 9-speed der with a clutch). This keeps the der arm much tighter than typical, which results in less of your chain flopping around like a.... well, you get the picture. Less chain flop = less chance of it falling off the front chainring. Oh, and I got a Raceface narrow-wide chainring as well, which has an every-other-tooth width difference that aids in not dropping the chain.
Of course, the chain-drop issue is especially pertinent when you try to ride a rigid steel bike on gnarly Hawai'i trails -- we got plenty da kine roots and rocks, jus' gotta work 'um and geev 'um (that's da pidgin kine the local downhill riders talk). Anyway, the plus-sized tires (3.0 inches wide) do allow for slightly lower tire pressure and the resulting slight increase in shock absorption. However, it doesn't amount to a whole hell of a lot on these trails where everyone in their right mind rides a full suspension rig.
Speaking of 29 plus... It's a 29er wheel with a fatter rim (50mm vs your usual, like, 25mm) and a 29 inch tire with more girth (3.0 inches vs, say, 2.3 or 2.5 inches). Doesn't sound like much difference, but it makes for a floaty ride with a less-pronounced snowshoe effect like you get from a true fatbike.
I also set this thing up tubeless, DIY-style (also known as "ghetto" or "split" tubeless). This means you make non-tubeless-ready tires and rims into tubeless by using stuff like a cut-up tube, maybe some tape, and some tire sealant like Stan's (or nock-off brand or homemade). So, in case you don't already know, and to be totally clear here, tubeless = relying on tire sealant instead of an inflatable inner tube. Maybe I'll do a blog post on how to do this ghetto tubeless thing yourself... or, to be more politically correct, since you won't find many bike-blog-reading, english-speaking mountain bikers living in our many fantastic GHETTOS in this world, I'll call it split tubeless instead.
I love the feel of a rigid bike. Whenever I hop on a friend's FS bike, it feels like a ridiculous bouncy johnny-jump-up toy of some sort. And Surly always nails it with finishes and graphics -- that's the whole appeal of the brand. BUT, ALAS..... as I become more speed-oriented and serious about racing, I must admit, this thing is a beast. Climbing hills feels like I'm dragging along a dead horse behind me, or at least a small dead pig, really. It's also a total pain in the ass to put in my car, in anybody's car, in the bike stand, in my house, or anywhere, really. In case you don't know that I'm talking about, IT'S HEAVY AND BIG. Most days I wish it were carbon (please don't tell the Surly gods I said that) and just normal 29er, minus the plus.