Honestly, as awesome as seeing this guys square off would be. and as close as the margin of victory would be, I think under the circumstances given, this is Taskmaster's fight to loose.
I think physicals between the two are too close to call, so we probably need to look at skill first. Now while both fighters perform at a level where it's very hard to definitively say one is more skilled than they other, I think despite all the styles Batman has mastered, Tasky still has a much deeper 'toolbox' of Hand to Hand techniques he can call than Bats does so I'd give him an edge in straight up slug fests.
Now gadgets, Batman always has a few equalizers up his sleeve to give him an edge against those rare few opponents that might actually be better, stronger or faster than him. But I have always understood Taskmasters 'Standard' armaments to include his sword, his shield, a high powered side arm, and a bow with duplicates of most of Hawkeye's trick arrows. The trick arrows I think are likely to be roughly equal to any little gadgets Bats has in his utility belt, and he comes to the fight with some straight up weapons as well, so I think Tasky has the edge in Gadgets.
Batman's clear edge comes in intelligence, tactics and just sheer will to win. Tasky's no slouch int his arena, but I think he probably relies on his natural abilities just a bit too much, and if anyone is going to find a sneaky or clever way to win, or just be too stubborn to loose that it's batman. That said, that's still essentially one advantage in Bats favor and two in Tasky's favor. I think Batman can keep this fight close, but all things being equal I think Taskmaster should take this by a narrow margin.