As a children's choir director at the time, I was appalled at the ranges, etc. when we saw & heard them in her training session. Plus a lot of her music is technically awkward & unpedagogical - puts kids at risk for twisting and stuff like that. BUT.....
That said, I know teachers who have used them and loved them, plus they are total crowd pleasers with parents. You would want to be sure and get plenty of help from parents on costumes, stage sets, etc., which I think could really spread a lot of fun & good will around, not to mention the glorious studio promotion it would do... I think they would be PERFECT for a summer camp or something like that. If you do one, be sure to report back.