Probably won't be missing out much in the first two films; two part compilation of the series. Seems like same soundtrack and OP and all. Probably cut out and put in a few scenes at best, I would assume.
Just gotta wait around for the third film. （ ´_ゝ`）
Though, if this ever goes to DVD/BD, at least it will be a lot easier to get three movies over an anime box series.