I like Caulker, but I usually spend more time on Ambergris Caye because I have friends there. Caulker is a good base of operations if you're on a budget because rooms are cheaper and it's easier/cheaper/faster to get to the mainland via the water taxi, when compared to Ambergris. Caulker has just about zero nightlife, whereas Ambergris has quite a few beachfront bars with old guys playing Jimmy Buffet tunes. If that floats your boat, bueno. Ambergris has more choices for meals, although I've never been so impressed with them that I'd go out of my way. It really does boil down to what you want to do with your vacation time. Ambergris is hyper, a lot like being in a gold rush boom town. Caulker is comatose, but I've always enjoyed my stay there.