This is completely dependent on what you are wanting or looking for. The different sites offer something unique. Some are closer to the marina and Trails End, Some closer to the Meadows, or the pool. Some loops are too small for larger campers, while others have no sandpad and are thus not usable for tents. Some people like being closer to the action while others say that was why they brought their bikes or rented a golf cart so they could be away from the attractions but be able to get there with ease.
Personally I like the 400 loop. The preferred sites are closer to the marina and Trail's End, but are somewhat cramped to me and they have a sandpad which I do not want. The 400 loop is really just as close plus it is all concrete and pet friendly.
So, is there anything specific you are wanting in a site?