i run a trials bike as a trail bike all the time. the front trials tire will affect your cornering ability, but you get amazing slow speed handling, it will go where you point it. you will no longer be stuck in ruts...you will find yourself actually aiming for the bad lines.....playing in and out of ruts...
bad stuff: terrible in the mud, tire will not clean out, and it kinda skates a bit. also, it will break loose early in hard fast cornering, kinda unnerving..... if you ride fast and loose, you'll hate it. if you ride hard technical stuff, you'll love it, you'll wonder why you don't just ride a trials bike..
for non trials tires the m12/s12 are hard to beat - but expensive and wear out quickly...