My simple opinion for this would be me labeling it as the middle-man of ant movies: better than Antz, not better than a Bug's Life.
As soon as I saw the trailer I knew I was going to like it, since what I think the other ant movies lacked was decent human interaction. I'm quite sure I stepped on plenty of ants in my childhood years, and I do remember my parents lecturing me, saying something like "imagine how you would feel if you were an ant." I'm glad someone finally decided to make an animated movie on that thought.
The story is exactly what a kid's movie needs to be: not dramatic, silly, comical, no excess and unnecessary romance, and there is a series of conflicts that concerns the kid himself, making him learn an effective, good moral by the end. I always start treating ants I see on the ground a bit better after seeing these kinds of movies. (And may I mention that I thought it was quite amusing that the ants here are forbidden from going into the house, something that annoys me about ants in real life.)
I fell in love with the designs, they're way more original and interesting than in the other movies, and they finally did the ant anatomy correctly and efficently, something that bugged me (HAHAHA BUG) about the other movies as well. The characters have likeable, varying personalities to match.
I definetly recommend seeing it if you don't mind the lack of anything to humor the adults. If you got to see it in 3D, that was amazing, and be glad you did.