I bought a book a few years ago called "How to choose a Bible version"
It had a chart section where they compared lots of translations on lots of criteria which included, accuracy of translation, consistency of translation, ease to read, acknowledged if it was a paraphrase etc.
NWT was listed. It scored reasonably well on consistency but pretty poorly on accuracy of translation!
They said it merited acknowledgement for the consistent use of "Jehovah" in rendering the Divine name in the OT. But scored it "nil point" (a la Eurovision song contest, non Europeans -don't ask) for using "Jehovah" in the NT.
They said it was fairly easy to read but was (interestingly I thought) not in anyway the best as far as ease and clarity went (try telling a JW THAT!)
So they didn't totally trash it or ignor it. I think they scored it 4/10. I'll check when I get home.