We like Boyd's in KW. I have never found the sites to be any smaller than any of the other Keys campgrounds. Sure, they have some that are smaller and some that are larger like most others. It is all about location to us. From Boyd's you can take a taxi or a bus into downtown KW. Some parts of downtown KW, most of it actually, is somewhat "adult" oriented. If I just want to be in the Keys, then we have stayed at others farther out of town, such as the KOA. Geiger Marina and RV is a fun place as well, a bit more rustic and old Florida but a good place to stay and eat. We have never had any luck getting into the state parks down on the Keys but they do look good when driving by.
As mentioned above, everything in the Keys is expensive. Some forum members will chime in I am sure, and tell you Boyd's isn't on Key West. But Key West is the name of the town and of a specific key. The town takes in more than one key, including Stock Island, which is where Boyd's is located with a Key West address on their mail address. A somewhat meaningless argument to me. We like to spend Thanksgiving and around Spring Break in the lower Keys.