Summary: Had an SG 4 which was fine for me. Then, when I couldn't recharge it because of the coupling connection on the unit (second time it happened ...first time they fixed it for free and told me it was a design flaw) and Sky Golf told me it would be $40 to fix it I got steamed and just let my membership expire. I was actually looking into laser rangefinders but realized that at my level of play it was more trouble than it was worth.
Summary: I really like my sgx, it has some great features but it is a little slow when marking the ball and advancing between holes. Also I am not real happy about the fact that it doesn't allow you to map your own courses like th sg5. Well at least I haven't been able to figure out how to do it.