What has surprised me most about Hill has been his slashing ability. He's quick and crafty, and gets into the paint pretty easily. If he can become a consistent finisher, he could become a very dangerous scorer. Mason has also impressed with his ball-handling abilities and ability to penetrate. He's definitely a gunner, but he's shown the occasional ability to get to the basket and to the line.
Since the dawn of the Big Three, the Spurs have never really had any consistent slashers outside of Tony and Manu. Now they might have a third and possible fourth, giving them some completely new options and opponents a new wrinkle to figure out.