I built one over the summer, with the idea of having it as a rigid 29er to complement my 1*10 full-suss.
It’s a very different game, initially it hurt like hell climbing. Not so much in the legs, but my lungs. I felt like I was about the puke them up. Now, though, I’ve gotten used to it, the bike is fast and light, something I really like. It is slower on the flat, but on the down I’m as fast as everyone else (despite being rigid… its amazing what difference those bigger wheels make) and on the ups I leave them all behind.
I still prefer the full-suss for the local woods type runs though, or anything really rough/steep for that matter.
The whole zero-maintainance thing is great. Permanently caked in mud, and it works the same as when clean, unlike the full-suss which needs to be looked after to work properly.
Love it, but I’m still undecided if I would only own a SS or not.