The reality is there are too many KOA's to just say I'm avoiding them all.
Some are priced right, some maybe a bit expensive. Nevertheless they do try to maintain a decent standard.
At the end of the day they are all a bit different with different price points.
Trying to paint them all with a broad brush is silly.
Rate/treat them individually on their own merits. In many cases they are the best game around.
When it come to quality I have been to a lot worse places than the KOA.
When it comes to price I have been to place more expensive than the KOA.
If traveling in uncharted territory, KOA's are generally a good place to start if price is not your only criteria.