Honestly, I've never had terrible park food (mostly since we pack a lunch).
I can't say anything about Disney's park food price wise (VIP meal tickets=awesome!), but their food was filling and really varied. Everyone got what they wanted without having to travel far. My favorite was...actually they were all awesome.
Midway Market for the live was the first time I ate at Cedar Point (Minus employee food), and it was a fairly good value. All the food was hot and filling, and the staff was nice.
Worst would be at King's Island I guess. The Skyway was awesome (surprise, I don't like chili), and really liked the chili spaghetti thing, but the western place where we had lunch had very expensive food that wasn't great. Though, I had a plain chicken breast.
Didn't eat at SFGAm (Employee food was ****, though. Moldy buns...), and didn't have anything besides funnel cakes and a coke at SFoG.
Yup, that's about it.