I haven't been to Sears Point since they changed the name to infineon, but at the time I found it pretty similar to Thunderhill with the elevation changes and the dead-grass look. Personally I like Thunderhill a lot more -- I find Thunderhill's layout flows a bit more continuously from one turn to the next. Plus Thunderhill has a lot less walls and is cheaper/closer for me.
I think you'll have a blast though -- unless they've changed the track layout in recent years, you could get a decent feel for the course by playing Grand Turismo 4