I saw both of them. Can't recall much of Waterfield although I did see him in the 49 NFL championship game against the Eagles on a rainy muddy Coliseum field. They lost 14-0. But his reputation was he was the best of the best in terms of being a field general. Not only was he the star qb but he also punted, kicked FGs, and played defensive back. Did see more of VanBrocklin and his long beautiful spiral passes including the 71 yd to Tom Fears to win the 51 NFL Championship game.
But its always difficult to compare players from different eras.