Our local KTM dealer sells the Pirelli MT-16 for 50 bucks. I put one on and it worked OK at first but as soon as the knobs lost their sharp front edge it turned to useless on even a moderate climb. I was getting stuck on roots that didn't even stick up one inch above ground - in fact the root wasn't as tall as the knobs on my tire. This was on a 15-20 degree climb, damp but hardly slippery, and nothing blocking front tire. Once it breaks traction on something it can't "dig" into it won't get the traction back. After only 4 or 5 rides I took the MT-16 off.
I know this sounds at odds with what others have said about this tire but it really isn't - tires perform differently under different conditions. My riding is on intermediate to hard terrain with a lot of tough hill climbs. On hills with intermediate to hard terrain a trials tire works way better than a knobby- on a hill that a motocross rider would call good terrain (soft and sticky) a trials tire works almost as good as a knobby - on a hill that has deep sand,shell,dust, or leaves a trials tire is much worse.
The Cheng Shin C755 seems softer than the other intermediate to hard terrain tires so it may wear a little faster than the others but it hooks up better on the hills than the other do after a little wear so you'll probably keep this tire on longer than the others if you ride big hills. This tire is only $40 (4.60x18) at Rocky Mtn. If you don't ride hills other tires mentioned would be a better choice.