I'll be honest, I didn't want to really like the film version. I have a king-sized soft spot for the ramshackle silliness of the TV drama, and wasn't keen on a flash big-budget version strutting around the place, giving it all that, and ruining my memories of the TV show.
As it was, I did enjoy it. It's a darker version of the story, with the film leaving out the whole crime busting plot line (and the zombies) and instead focusing on the battle against DigiCap and the search engine they'd designed. The characters are more sharply defined in the film version, too. Box's fear of women is more overt, and Page's stutter is so bad he can barely complete a sentence.
Trying to decide which is best is difficult. Akira is better acted in the film, by some margin, with Yamada Yu easily outclassing Kosaka Yuka. Then again, the head of DigiCap seems more malevolent and interesting in the TV series, despite the comedy trappings. Kitamura Kazuki gives the role a slightly deranged edge that the film lacks.
They're different enough that they don't tread on each others' toes and I think that disliking one won't effect how you feel about the other. The TV show is energetic and keen to be loved, while the film is a cool, distant, good looking version of the same story. But the televised version has the Daruma character, a better ending and a slightly more genuine otaku feel to it. So, on balance, the series takes the victory.
Hmm, you'd think they'd be happier about it...