English is not my native language, but I read a lot of books in this language. Helped me to improve my vocabulary
I have also read many books in Czech, my native language and the only other one I know well enough to read books in. If the book was written in English, I prefer English - if for nothing else, then because I don't want to wait years for them to be released in Czech, if ever. Translated books I have read... some were great, for example Jan Kanturek, who translates Terry Pratchett books, won several main prizes for it. I have read those books in both English and Czech and I understand exactly why he want those prizes. Pure genius.
On the other hand, I have read several horrible short stories, something nagged me about it, so I look who translated them... you can guess, same name every time. And I almost put those autors on my black list of "never again". When you read the books in their native language and you are good enough to enjoy them, great, that's a way to go.