We've only stayed at two KOA's, sorry to say. We think they're fairly "pricey" too however there's something to be said for "you get what you pay for". The first stay was years ago in West Yellowstone MT and that was a very good experience. The second stay was just last September in Petaluma CA, our experience there was OUTSTANDING! Both of us were really impressed with that facility! Very clean and well organized, couldn't help noticing that the employees were always working on something around the campground. We took their San Francisco city tour with John one of their tour guides, which was in itself outstanding and worth EVERY penny!
We like a lot of others prefer state and city parks over commercial parks but we wouldn't hesitate to use KOA if the need were there.
Dan