Thinking of getting a golf GPS system.

I have always had trouble gauging yardage, so I am thinking about getting one. I am currently looking to spend less than $250 on it. The ones I am looking at are the SkyCaddie SG2.5, SkyCaddie SG 3, Sonocaddie V100, and the iGolf Caddie II. I am leaning toward the SG 2.5, but don’t like the idea of having to purchase a membership to download courses. I am not a big time traveler, and only play a couple of times a year out of state other than that I play about 5-6 different courses. If anyone has used any of them, and could give me some feedback it would be greatly appreciated. I would also like to be able to be able to go to the range, and get the average for each club I have, that way I can be more accurate. Is there a way to do that?