for me personally, I'd rather have the disparity of talk. I mean, it does take place in the UK, so it makes it feel much more authentic to me. Most of the kids i know that have read it, love it, and jump on terms like "boogies"
Then again, I've always loved the imported British television and my roomie is from the UK, so i might have a different opinion.
Is there any difference between the UK version and the US version? If so, i might have to import and pretend it's a new series :-D