I can only talk about the film, not having read or seen the play, and it's been a few years since I've watched it, but from what I remember, Claudio is the innocent party in all the dealings, and it plays out to a happy ending for all.
For a Brannagh adaptation, it's one of the ones I enjoy most, as it appears to be set in the correct time period, the cinematography is beautiful, and the dialogue between the actors seems to flow so well that you quickly forget you're watching a Shakespeare play and I feel engrossed in the story really easily.
I watched his version of Love's Labour's Lost again a couple of months ago, and I think I might have to dig out my DVD of Much Ado this weekend for another viewing, particularly if it started raining again!