I am biased because I'm an Okie and graduated from OU-Norman campus. San Francisco is a great city, I love it there! So much to do and see. Lots of culture.
I really like Oklahoma City. It's constantly growing and it's nice because it's has a big city feel but it's not massive. The OU medical center is right by downtown (Bricktown is lots of fun!). I lived in Norman for 5 years so I was really close to OKC. OKC is just a couple of hours from Dallas and Tulsa. Oh and the cost of living is relatively low compared to San Francisco!
But that's just my biased view! 😀