FWIW:
All translations, 100% of them, will have some bias somewhere. It's impossible to not have bias when translating such a large collection of books written by different men with different viewpoints from different cultures over many centuries.
The NWT, after discounting its obvious biases*, is probably a pretty decent translation for 98 - 99% of its contents.
* examples: the comma in Luke 23:43, 1 Corinthians 7:36 (bad enough when it was "toward his virginity", now it is inexcusably biased as "by remaining unmarried"), many if not most of its insertions of "Jehovah" into the NT, etc.