Bought a Ko-ken "Attack Driver" (Tora! Tora!, and Banzai!) for 780NT which does seem to work better than the Thorsen one I already had here and has a nice quality feel to it, though it only came with 4 bits.
There were King Tony and Force sets at around 500 with more bits, but I decided I'd get the most expensive driver I could find and worry about bits later.
Good tools are nice, and in this case worth the cost, because it convinced me that impact drivers actually do work, which I'd never been sure of before, probably because I wasn't using them right, was using cheap ones, or both.