Our camping experience in Anacapa island was wonderful and unique, we were lucky enough to have the island all by ourselves during our stay, and we could explore the whole island undisturbed once the day trippers left around 3 PM, the ranger was super nice and knowledgeable, the restrooms were one of the cleanest we've been in all the NPS system, the island felt small and cozy, unbeatable vistas all around.
During our stay we shared the island with 9,999,999 seagulls, they were very territorial between them, so much so that the would kill between them, but they never bothered us a bit, never tried to snatch our food or didn't even came close to the trash bags, but please make sure to always keep food in lockers, at night little deer mice will come and check if you had any leftovers, so don't leave anything outside.
In short, great experience, so close to mainland yet so different, will definitely recommend.