Hmmm... I like the series better, but just because...
...there was just so much more of Hitomi and Van's story in it. :)
(spoilers)
In the movie, I'm startled and maybe just a bit disappointed by how easily/quickly Hitomi and Van get together. During the series, we see how subtly Van likes Hitomi (Such as when Hitomi changes into one of the princess' dresses and Van is so taken aback that he silences Merle's fat mouth by a squash on the head... hehe, one of my favorite parts) Or when Van notices Hitomi and Alan holding each other. It was the slow romance of Hitomi and Van in the series that kept my attention (among other things.)
I'm also disappointed that Alan was pretty much ignored in the movie... even though I know there wasn't enough time for his story.... but still... It's a beautifully animated movie and another way of looking at the series.