Movies of shows are a mixed bag; on the one hand, there's a bigger budget and more time so there's potential to do crazy cool stuff; with animes this means much much much better animation (I'll use Rurouni Kenshin as an example; the movie was actually weird as it had the exact same animation, different and shitty voice actors, and was essentially two episodes strung together, but the OVA was brilliantly animated and way cool). However, there's some pitfalls. The movie has to remain true to the show while not being just two episodes of the show strung together, and it also has to fit into the continuity of the show and possibly leaving it open for continuation. This is where Serenity ran into trouble; it was true to the show and cool and all but wasn't hugely more exciting than two episodes until suddenly Whedon started killing characters and setting up really huge battles and stuff at which point it didn't really fit and if he ever manages to continue the show, it's gonna be really weird without Wash and Shephard Book.
/rant. This is a good sign I should go to bed or something.
/rant. This is a good sign I should go to bed or something.