I LOVE Zootopia. I haven't been this much in love with any movie since "Up." It's funny, touching, suspenseful, has action and twists, a good story, fun Disney in-jokes, great characters and performances. I would follow Judy and Nick on any adventure (and Chief Bogo had better be there, too). Everyone should see Zootopia, whether or not they have kids or think they like animated films.
I haven't seen Minions, but I'm assuming it's more of a "straight comedy" - silly and enjoyable, but not particularly meaty or memorable. Animated films often seem to get lumped into one category, even when they're really quite different. Think of all the live action movies you've seen: people don't generally compare a silly comedy to a period drama to a popcorn action flick just because they're all movies. They're totally different stories that happen to be told through the same medium.
See Zootopia. And the more spoiler-free you are going in, the better; just sit back and enjoy the surprises.