Well, I was born and raised in Solana Beach and now my family and I live in Encinitas, so I guess I can compare the two.

Encinitas has a bit more going on in terms of shopping, restaurants, grocery stores, all the stuff you need for daily life. Solana Beach is much more of a bedroom community. It's very nice, don't get me wrong, but lots of people in Solana Beach drive to Encinitas to do a lot of shopping (Target, Trader Joes, that kind of stuff). So take that into consideration, if that's an issue for you.
I surf, too, so I definitely can relate. I couldn't live more than 15 minutes from the beach. Being able to jump into the water for a quick session before work is a big deal for me, and I can do that cuz we're only about 7 minutes from the beach.
The commute southbound to Mission Valley is bad in the mornings, but usually only through Carlsbad and northern Encinitas (Leucadia, etc.) At Cardiff and into Solana Beach, it's usually full speed. I'd say you could be in Mission Valley in 30 minutes, with traffic. Don't know if the Coaster-Trolley from Old Town route would work for you.
good luck.