Prefacing this by saying I'm a 40 year old who has played most of the games and watched the other two movies, I took my partner and 13 year old step son to watch this who both enjoyed it a lot.
It's silly, but it's about anthropomorphic animals so that's fine. There are some great ones liners. The story has been panned by some critics who clearly don't realise that it was based on the game Sonic Adventure 2. It pulls a lot from that game.
Its basically an enjoyable adventure for the family which should mostly please long time Sonic fans, new ones and parents who don't know much about it. Overall recommend.