I've used these tires in the past, when they first came out (apparently 2011). Since then I've tried several brands and tires - I enjoy the mechanical aspect of the mountain bike nearly as much as the actual riding, so I'm always changing things, especially tires.
Over time I ended up sticking to Maxxis primarily - most recently the Ikon 2.35 front / rear, or DHRII front / SS rear, etc. Bike is the Yeti 4.5. Terrain is technical rocky, big climbs and a high preference to difficult. Believe it or not the Ikon 2.35 is hard to beat for traction and speed. But.
I recently threw on the Mountain King II 29x2.4 front and back (I would normally run the XKing in back, but wanted to try something different). First ride out was a fairly smooth 2000 foot climb, then a fun, choppy, fast, rocky descent and back into smoother terrain.
As others have said, I forgot how fast these tires are - this is probably the most surprising aspect. For as aggressive and "blocky" as they are, they feel smooth and quick on the trail.
Cornering felt excellent, but I'm still a little hesitant to push it until I reacquaint myself with this tire. The rear wheel seems to lock up very easily (skid) with this as a rear tire, but I may have to adjust my technique.
I'm 175lbs and running 17psi front / 20 rear - the sidewalls are so rigid, you can easily get away with lower-than-normal pressures. From my past experience, the ProTection sidewalls are very reliable as well.
All in all, again I feel there isn't much talk about this tire, but should be (even though it is on the way out with a 2018 replacement as I understand).
Regarding width: I’m getting just over 2.3” at 17/20 psi and the full 2.4” with 50psi (done to stretch tires initially).
Tires are very subjective in my opinion, but I'm definitely happy with them and will leave them on for a while.