Saw it last night. Wasn't impressed.
The TV version, although with the usual BBC five-dollar effects budget, was much better IMO. It had at least three times the level of wit, which is what you come to this series for, and twice the level of acting.
And frankly, nobody walks into a Hitchhiker's movie waiting to see if Arthur gets the girl. Geez.
I've read the books, which tended to get a bit morose in the later volumes, and have not heard the radio version.