I noticed on my XR500 the difference a quality tire makes in the treadwear.. The ChengShin, and all those brands cost about $100 around here, but they're a soft compound, and in gravel and shale, they get eaten up... I wore about 3/16th off the rear tire in a 60 mile ride, and that's before I was really used to the bike. Now I spent $180 on a Dunlop tire, and it wears much better, the leading edges of the treads stay sharper, giving you better traction through the life of the tire. Oh, and I have a trailer hitch on the bike and routinely tow a 600 lb trailer, so it gets some hard work.
And yes, that tire is STIFF... I'm quite sure I could ride it flat if I was nice to it... When its off the rim you can sit on it and it doesn't fold or collapse.