One For All isn't a very fun experience.
Sure once in a while you find that really nice group of people who enjoy whoever they get... But that only happens in a monumentally minuscule amount of these games. Every other game starts with about 5 other games that someone dodged because someone banned the champion they wanted. Then you finally come to an agreement to a single champion to play as. But the SECOND things start going south, the morale is no longer there. Every OFA I've played has had an AFK because they didn't get the champion they wanted, or because someone isn't good at the champion on their team (or it's them).
Anyway that's my take on this game mode. Its silliness factor is incredibly inconsistent and clouded by children's desire to win and get what they want.