Yeah, it is strange in that the first movie is just a compacted remake of the first several episodes. Movie 2 is mostly a remake of most of the rest of the series, but then has a very different ending, introduces a new character, and changes the arcs/backgrounds of other characters.

Movies 3 and 4 are completely different from the original series.

If you like stuff in the magical girl genre (along the lines of Sailor Moon), "Madoka Magica" seems quite good from what I have heard/seen (I saw the first couple episodes before CrunchyRoll started demanding login to even watch their free stuff). Not sure where else to watch it, though.