I basically live at both tracks.
Sears Point is very technical. Not many high speed straights cept for the front straight. Turn 1 is high entry speed but be ready for T2, you are going uphill then banking into a hard right turn and it catches many off-guard.
Walls are absolutely everywhere and very close. @ T-hill if you go off you slide forever till you hit a cow or cow dung. At Sears Point you hit concrete.
T-11 is the most awesome turn in the world. You're going one direction then you're going right back the other direction. If you slide here, it's tires you'll hit. Please don't slide here.
The facilities are top-notch whereas @ T-hill it's a little bit hick. There aren't many restaurants near the track. You'll have to drive into Novato or Sonoma. Don't drive or stay in Vallejo. I live there. It sucks. Don't do it.
If you need more info on anything, lemme know.