Very different. San Diego is not a mega city like LA or the great Bay Area. Much better weather than SF, seems a bit more relaxed pace and not as overrun.
I wouldn't be surprised if the massive, long-standing military presence in/around San Diego is a factor for the region being more conservative than most of coastal California.
This is part of the reason. Another part is that typically the closer you get to the equator in the US the more conservative. It's related to the reason why beach towns typically have bad food and no real culture.