Where are you from? I live two hours north of SD, in the Inland Empire part of Southern California, and have a sister who lives in SD. She works in one of the hospitals. One of my nephews lived there for a while. It is kind of hard for a young person starting out and he had to live in a very small place downtown. The upside to that is he was blocks away from the bayfront.
There are several neighborhoods. My sister lives in Kearney Mesa area, which seems pretty nice. I stayed with her a few days once. If you move to SD, it is a safe bet you will have friends or family want to stay with you from time to time! Of course, you also can check out many of the hotels and give recommendations.
I have visited San Diego many times, although it has been awhile. I love Balboa Park. If I lived in SD, I would be there often. The feeling there is relaxed, yet lots to see. There is usually a mix of locals enjoying the day and tourists. Museums, pretty architechure, small gardens, theater, and the zoo. Just love it.
There are so many places to see and a good varitey of restaurants. Downtown encompasses the San Diego Bay, Little Italy, and Gaslamp District, as well as Balboa Park. Just across the SD Bay is Coronado, which has a village feeling and a historic hotel on a public beach. Old Town area has the mission and a historic church. La Jolla has beautiful coastline and a different type of a village feel.
We think of the people in SD as being more authentic than LA, or at least the general atmosphere.
I like the feeling of SD being a Navy town too.