I find the food on BA, LH and AF to be much, much better than UA. UA’s seat is slightly better, but I’m fine with all of them. The Polaris lounge is great - where they exist. AF and BA pre-boarding dining are almost as good - where they exist (like IAD).
Also, I don’t mind CDG Terminal 2 (AF), but Terminal 1 (Star Alliance) is bad. Only AF has an arrivals lounge at CDG.