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A rangefinder is a laser. A GPS system would have courses that you download.
I don't know much about GPS's but I think a Rangefinder (laser) is the way to go. I understand that gps's are convenient, but rangefinders give you yardage to anywhere.
Look for any bushnell or a leupold and that should do the trick.
Those watches do look handy but like I said before I'm not sure if they have additional fees for courses or what. If he is very serious about his game I'd look for a basic rangefinder Leupold gx-1 or bushnell v2