Well, I can tell you that they shed mud/wet sand very well. It is because the spaces between the big knobs aren't filled with smaller knobs like you see on other tires such as the Panaracer Fire xc's and the IRC Mythos. Those tires roll better than the MotoRaptor's on pavement and hardpack because of those small knobs in between. So, as you can see it is a trade off. I will pedal a little harder (barely enough to notice) for a few advantages such as better clearing and better looks (once again, personal preference).
I rode Flatwoods on Wednesday and I was really impressed with the tires. At 35-36psi they had great traction in the turns (leaned way over) and took the bite out of the roots (especially on Indian and Heartbreak Ridge).
As far as the "size" of the tires, they are 2.14's and they pretty much look like it. They might be a little "taller" than other 2.1's but I'm not positive about that. On my bike (Gary Fisher genesis hardtail) they are great all around tires and as long as they don't fall apart prematurely (I doubt it, WTB makes quality stuff), I won't be doing any more tire swapping for a while!