I've never liked the concept of using a GPS. Part of the game is visually sizing up the distance to the green and the general layout of a hole. It's just part of the skill, and benefits experienced players. Sure, you have the 100,150, and 200 yard markers as benchmarks, but those can only tell you so much. Call me a stodgy purist if you must, but something about using a GPS seems...impure.
And as for the 4 putt...well, we've all been there before.