We had dinner at the Fly Trap on Folsom last night. I would call it good to very good. It's not fancy, not a lot of frou-frou, but the food was good, solidly prepared and lots of it. They also have a piano player that played lots of "oldies."
This is an old time SF restaurant, founded in I believe 1911 and of course it has moved a couple of times during it's tenure. They have many "old time" dishes such as liver and onions, coq au vin, petrale sole (which I had) along with some good, more upscale specials. My wife had sea bass with a mushroom sauce served on mash potatoes and pronounced it very good. The petrale was pan sauted with a butter/caper/lemon sauce and was two very large fillets.
All in all, a nice evening with better than average food and very good service. They also have several good wines by the glass at reasonable pricing.