I'm willing to believe the Dirt Rag staffer's experience over anyone else in this thread, but why fixed on the trails? Disregarding the need for skidding (which newbies, myself included, can do with brakes and gears), you're going to annihilate yourself on a log sooner or later. It's easy enough to do on a freewheel if you don't orient your pedals correctly, but on a fixed it's almost inevitable..