I have to second the two stroke for trails. I also love how the power explodes and tosses you around the trail. A four stroke can "chug" and offer some snappy torque right off idle which is why most people talk about the "low end torque". Truth be told, the two stroke has just as much, but you don't get it quite as low.
I can cruise around at a higher rpm (to get closer to the power band) and it's just like a toggle switch. Snap the throttle and lookout. If you are really chuggin along at low-low-low rpms, then yes, the thumpers have more on tap. Nothing that some clutch action can't handle though. :)
And also, maintenance all depends on you. If you care about your bike, you will probably be working on it after every ride. the filter or tranny oil can never be too clean. I am either inspecting, cleaning, or adjusting something after almost every ride with my two stroke. But being a more simple motor, it is much easier to work around IMO.
Micah
P.S. There are tricks that I can do to restore low end power. They make heavier flywheels, torque reeds, torque pipe or even selective porting of the cylinder. I've ridden some VERY torquey 2 strokes, but you usually sacrifice top end power. And at this point, I'll use the clutch a little more down low, just to win the drag race on top :)