The bus runs every 20 minutes, and the journey takes 30 minutes. The airport is only 10 miles from central Bristol, but the road is a two lane, and traffic into/out of Bristol is pretty bad.
After getting my rental car, I headed SW on A38, but one can go NE on A38 for a few miles and then take B3130, either east towards Bath or west towards M5, to bypass Bristol.
The Texaco station about 3 miles NE of BRS has good prices. I filled up for 84.9 p/Litre before returning the car, which is about 4-5 p cheaper than most stations elsewhere. [I did fill up for 81.9 in Falmouth, though.]
I arrived BRS on Saturday. The flight was about 30-40% full, and many people including myself could spread out in the back. The landing, however, was just as rough in strong wind. In fact, something fell in the rear galley, and I could hear one of the FA says "sh_t".
Overall, I also like BRS a lot. Renting a car is so easy there. And we were in the air about 5 minutes after scheduled departure time, arriving EWR half an hour early. I managed to get on an earlier flight back to IAH yesterday on standby.