Both are nice. Windy Hill is in a location about 2 hrs west of Belize City, close to the town of San Ignacio, several Mayan Ruins, River activities, Guatemala border. The accommodations are individual thatched roof cabanas spread out on a lovely hillside. Above ground pool, full restaurant/ bar, easily accessible. Jaguar Paw is located about 30 miles West of BZ City, in the jungle, right at the mouth of a huge cave network which you can tube through. Close to the zoo, Monkey River wildlife park. Accommodations are pretty deluxe for Belize, with "theme rooms" (Laura Ashley, serengeti, asian, etc.) a fancy bar/restaurant, pool. Beautiful upscale place. Both would be pretty good for kids - Windy Hill because they have large cabanas, cool birds around, Tv, mini fridges, big property. Jaguar Paw's main feature for kids is probably the swimming by the cave mouth.
Depends on what you are looking for... www.barbsbelize.com