Of all the GPS units that have come out in the past five years, I have to say that I think the Golf GPS has advanced the most in the last few. Golf GPS units used to be based on older technology, with a thin layer of Golf-only benefits skimmed on the top like frosting on a dieter's cake. Not anymore.
The Garmin Approach G6 is pretty advanced, offering features that really can help your game. With over 25,000 courses preloaded (free), and the ability to have the G6 compute your average distance per club, your ability to see exactly which club you SHOULD play is a good thing. Whether or not you actually play that club is the mental game that is the other side of golf.
Other than the touchscreen, the features I like are the one touch button to access the scorecard, the 15-hour (read all weekend play) battery life, and the Lay-up arcs that show you where on the course certain clubs will drop you. Check out the video to learn more.