I am yet to read Tolkien's work in English... I have started, but at the time I was FINSIHING a re-read in Spanish and so finishing it up took precedense over starting it all over again
I must say, at least with the Spanish translation I have, while whoever translated it did an excelent job overall, there are things that just can't be translated... from the little bit I read of his work, it really is much better in English. As well the songs and general poetry in the books were translated into Spanish but not re-arranged so that they rhymed what so ever... and thus all the songs (that are quite beautiful in English) are an eyesore.
Still, it is an overal great work of translation...