Well, it all sort of depends on where you’re coming from, and where you’re going.
I only do one or two shows per year, flying in from abroad. On holiday, it’s easier to swallow that price and go for it. If I was British, driving in from somewhere, I would be more hesitant to paying it. Being there, as one of (if not THE) event and time of the year for me, I gladly pay more to get that marquee with seating, nicer restrooms and a pint of Spitfire Smooth. Only annoyance with that is that you have to pay for the beer. With the price involved, I would think it would come free, for example 3 pints free, the rest you pay for or something like that.
The seating is great. Never had any issues with people standing. Had one chap getting up every time the P-51’s flew by in 2008 to take pictures, but beside that, I never had any issues with people not sitting down.
For foreigners with a deep love for historic aviation, not being able to see these shows at home, I recommend it by far. It’s a once a year chance. Just go for it. You’re on holiday for crying out loud.