I went to BSB @ Silverstone a few years ago and was massively disappointed with the viewing (miles away from the track and behind high fences - rubbish compared to other BSB venues).
But motoGP is in a golden era so last year I did decide to go back to watch motoGP. This time we got seats in one of the grandstands and had an excellent view (compared to general admission tickets) but ultimately the weekend was obviously ruined by bad weather and circuit incompetence, with the racing being cancelled.
I might begrudgingly try again this year, but will wait till much nearer the time to see what the weather is like before I decide - it's not that far from me anyway.
Alternatively I reckon I could do an overseas round for the same cost or cheaper (cheap flight to Spain or ride to Assen) , albeit that necessitates a bit more time away from home.