I'm glad I went to see this, although Douglas Adams has been an interesting quantity over the years. If you've read his stuff beyond Hitchhikers like the rest of the Trilogy, Dirk Gently's Holistic Detective agency or even the Meaning of Liff, you'll be used to his gentle but "clever" humour. And his views on the media, like the old h2g2 project (went the way of the BBC).
The film had some nice touches, like the odd cameos from the actors in the original television series by the BBC, and the appearance of Marvin in a queue of aliens towards the end...