A healthy Howard displays dominance, but that dominance is bit misleading. His game is based almost entirely on sheer strength and athleticism—he has a poor post game, is not a great passer, and can't hit from outside of 8 feet to save his life. Gasol, while clearly a less-impressive physical specimen, can do all of these things while still getting a decent amount of points, rebounds, and blocks.
Of course, this is largely splitting hairs; I'd take the talents of either player (though not Dwight's mindset) in a heartbeat.