Really if you were to take a serious look at the work put into this translation of the Scriptures you would find as do many serious Bible Scholars and historians, that it is a very accurate and reliable work. Being regarded as such even by those who do not favor Jehovah's Witnesses. Note what just a little research reveals below regarding the New World Translation.
The master text used for translating the Old Testament into English was Kittel's Biblia Hebraica. The Hebrew texts, Biblia Hebraica Stuttgartensia and Biblia Hebraica Quinta, were used for preparing the latest version of this translation. Other works consulted in preparing the translation include Aramaic Targums, the Dead Sea Scrolls, the Samaritan Torah, the Greek Septuagint, the Latin Vulgate, the Masoretic Text, the Cairo Codex, the Aleppo Codex, Christian David Ginsburg's Hebrew Text, and the Leningrad Codex.
The Greek master text by the Cambridge University scholars B. F. Westcott and F. J. A. Hort (1881) was used as the basis for translating the New Testament into English. The committee involved in creating the New World Translation also referred to the Novum Testamentum Graece (18th edition, 1948) and to works by Catholic Jesuit scholars José M. Bover (1943) and Augustinus Merk (1948). The United Bible Societies' text (1975) and the Nestle-Aland text (1979) were used to update the footnotes in the 1984 version. Additional works consulted in preparing the New World Translation include the Armenian Version, Coptic Versions, the Latin Vulgate, Sixtine and Clementine Revised Latin Texts, Textus Receptus, the Johann Jakob Griesbach's Greek text, the Emphatic Diaglott, and various papyri.
This is just but a sampling of the tremendous work that was put into this translation of the Bible text.