I too have thought about transferring during this whole process. However, I truly believe that you should choose the school as if you are going to graduate from it. Also, I think all of us believe we can be in the top, however, the truth is not all of of CAN be. Someone's gotta fall elsewhere. Just try your best and see where that takes you. I'm no expert, but I do believe you'd get a good job coming from the top at either school. Do you want "Big Law"? What are your plans for after law school? If you want some huge high profile job, find another school. I don't like hearing that either, but your chances are better with a better school. However, I'm not looking for "Big Law."
I live 70 miles from Sacramento and 90 from SF. Being so close, I don't think I'd be a very good judge of either. Personally, I'm tired of Northern California. That's why I was considering schools in SoCal. But the cost of living is just too high to put on loans (with interest!!!).
San Fran is frequently overcast and a bit depressing in my opinion. It can get pretty chilly at night even in the summer. I really hate the traffic! And the public transit isn't very reliable and takes forever. I used it during my undergrad years and I am SOOOO thankful those days are over! If you like city life, then SF is a good place. I don't find people especially friendly there. Many are into their own thing, earbuds in their ears worrying about their own problems. I guess that's society in general these days.
Sacramento isn't my favorite city either. I think the crime in both places is high enough. Old Town Sac is nice though. Also the newer places by the airport look nice. McGeorge is located in a bad neighborhood, unfortunately. Though, campus is fairly safe I've heard. McGeorge, despite being located away from its undergrad, does have a real campus feel. It's pretty big for just being a law school. The weather in Sac has its extremes. It's the same weather I experience 70 miles South. We get frost in the winters, but the winters are fairly mild. But the summers are really HOT. 90s are usual, but it does get into the 100s often enough. It's also very dry, which I prefer to humidity.
Since you're coming from Canada, SF's weather probably won't bother you as much as it does me. Sac might be pretty hot for you in the summer. I think both places offer night life and the like. But SF offers a bit more. I hope that helps. That's all I can really say about the cities themselves. Ask around 'cause everyone has different opinions. I think you'd enjoy this area more being that you haven't lived here your whole life. Good luck!