going to the british Grand Prix next year, and booking tickets. I've never been to Silverstone before, so not sure which tickets are the best to get. Looking for people who've been there and done that

Is the general admission ticket good - if I can go wherever I like round the outside of the circuit that sounds good. But is this limited because of the grandstands in all the best positions?
Is it worth going for one of the more expensive options? I'm not bothered about having cover, but I'd like the best 'bang for my buck'.
Basically I'd like your thoughts on which ticket to get. And fast, cause they seem to be selling quick!
cheers B