Vantaggi
NOV does allow family to be a priority and getting time off to take care of family is never an issue NOV seems to promote nice people into management roles. I have run across very few if any dictators in a management role. Most of the people that have strong personalities and are aggressive have a glass ceiling at NOV.
Svantaggi
Promotions and reviews are non existent. In my for years at NOV I have heard of only 1 engineer that has been moved out of engineering to a different role for possible career progression and have not seen one engineer moved to a more senior engineering position. Also there are no yearly reviews or reviews at all. It does make sense though, if you are not going to promote anyone why would you do reviews. Basically being an engineer at NOV is a job, do not expect a career.