So I'm gonna start by saying that I really liked the movie, but I have to look at it as an independent since there are too many inconsistencies between it and the show. Especially since the show already gave them an origin story so if i started comparing the two, my rating would drop.
That being said, I really liked the animation and the story was cute. However, there were two things that really threw me off:
First, Marinette's singing voice sounds NOTHING like her speaking voice. Personally, I don't really like musicals to begin with so it just ruined those moments for me.
***SPOILER?***
Also, at the end, all their identities had been revealed. Technically, this means that their miraculous are taken away, but the movie ends without resolving that. I heard that they're planning on a sequel so it will probably get resolved then but I can't imagine they can do a lot with it in the next one. We'll see I guess, though.