I had not heard of this translation before. Having read the preface, I can safely say that it has not been translated by computer, but by someone who has a good grasp of Esperanto. The translator has capitalised a great deal more things than is usual in Esperanto texts (such as "la Angla lingvo" = the English language). But that is possibly a minor quibble.
I think it must have been a very challenging book to translate, particularly because of Newspeak, which is of course essentially a version of English made more concise and deliberately brutish.
I can't vouch for all the book, having only read sections, but my initial impression is that, save for the sections of Newspeak, it is both grammatical and stylistically very good.
However, I would suggest that for someone just learning the language, it is better to stick to the canonical texts first, to ensure that you are learning from grammatically correct examples. The most important of these are Zamenhof's Fundamento de Esperanto and the Fundamenta Krestomatio. As a more modern alternative, David Richardson's "Esperanto: Learning and Using the International language" has a good selection of texts of gradually increasing difficulty.