Have you ever come across a book whose translation in another language you found superior to the original?

That's an intriguing question. I have to answer it in an unexpected way; when I've read works that were translated into English from other languages, I've always found them superior to their originals merely for the fact that I understood them better in English. That does not mean, of course, that the English translation made the book better, but I hope you get my meaning.

:) 

Yes and no. not a book, but a comic. "Donald Duck". It is much better in Danish.

Yes, a direct translation of the bible, word for word.  It is a sweet read.

not yet

Unfortunately, I don't speak another language well enough to be the judge.
Of authors writing in a language not their own, the Pole, Joseph Conrad, is reputed to be the master. His "Lord Jim" and "The Heart of Darkness" are excellent examples. He wrote English far better than most professional and natives of the tongue. His language sounds verbose compared to today, but sparse compared to Dickens.