My choice would be Chula Vista RV Resort. I consider it a 5 star RV park. Although it is expensive, it has the amenities and location that makes it a great base camp for the San Diego area.
We spend 3 months there every summer (most expensive rate)and have never had a bad experience. The grounds are well kept, staff is friendly and the park is safe.
An added advantage is the numerous RV related vendors that will come into the park to do repairs, clean and detail, replace or install appliances/accessories. Very convenient and the prices are reasonable.