(snip)
It's a piece of cake to edit that poorly played MIDI drum loop. It's a piece of cake to edit velocities, to tame or add dynamics where needed. It's a doddle to alter the reverb and EQ per drum so you can wet up the snare without wetting up the kick, too. Want a hair more or less swing on the part? Easy with MIDI. Want to move the backbeats ahead or behind VERY slightly to create push or pull? MIDI drums can do this. Feel the drummer was a bit busy? Start erasing notes out.

If an audio loop is perfection, you are good to go. Mind you, perfection for one tune might be too busy or not busy enough for another. Perfection might only work with all the other parts, basted in the same type of reverb/room sound. Not easy to do with most arranger's built in effects... and you can end up with a style where the drums simply feel 'disconnected'. I've already heard that on some of the Yamaha drum loops.

And that's the bottom line... if perfection doesn't come OOTB, with MIDI and a bit of work, it's doable. With audio, you are done!