Valley Paintball, Area 13, Combat Zone, JRVP-All well established rec fields, they all started similarly to GRP.
Air Assault, FSL, SPO-indoors in the twin cities; not really comparable.
Review:
GRP is a fun place to go. Rick does his best to keep a friendly atmosphere (some rough characters, but they grow on ya) and the prices very low, to make it worth the drive. The field itself is very new and he's made serious efforts at making it playable even before it's broken in. The regulars are good people, and if you like thick cover, here it is. Very similar to Sabin Field in the height of summer before Valley Paintball moved in.
The only negative issue I had was safety. The players and staff were not wary of barrel condoms at all, and once shot out, would move about 30 feet from the action and remove their goggles. But if you like your eyes, you can just leave your 'filers on.