Donaire is more technically skilled.
Pacquiao is more naturally skilled. If Pac never learned to box he'd still be a good fighter. I don't think I can say the same about Donaire.
Pac has some of the best footwork in any combat sport.
I think Donaire is smarter than Pac and possibly more adaptable.
Pac is the gameplan guy. He'll stick to the plan for 12 rounds unless he's feeling adventurous and wants to test the other guys' power.