Pros: The amenities available in the Hamilton Cove complex are nice, if you find the time to use them (tennis courts, swimming pool, access to a tiny pebble beach, etc.), but we didn't stay long enough to have the time to use them. The ocean view from the balcony is great. The unit included a golf cart, which you will need to go into town (but if you stay in town, you won't really need one as Avalon is very small and you can walk everywhere). Kitchen was well stocked if you're planning on cooking.
Cons: Parking your golf cart in town can be tricky on a busy weekend, and most streets have limited time parking. The front door lock was jamming, so it was super hard to lock and unlock the door, taking us several minutes to make the key find the "right" position. Balcony was pretty dirty, so we tried to keep the balcony door closed to avoid getting the outside debris inside the unit. There was a funny smell in the unit, possibly from being closed too long? On our first night on Catalina it got super cold, and there is only one tiny heater in the whole unit near the floor between the bathroom and the bedroom that needed to work for hours before the bedroom got warm enough for us to sleep, and we were still had to use every single blanket they provided.