Vantaggi
There is not much good to be said other than NOV is the biggest kid on the block (about 90% of the drilling rigs in the world has at least some if not all NOV equipment on them) and it has very deep corporate pockets. It has grown in part by buying out its competition.
Svantaggi
NOV-PCG is the most dysfunctional place that I have ever worked at. There is no true communication and coordination between different functions. Business in the oil patch is so good at this point in time that the most mismanaged company can make money. Millions of dollars are lost every year due jobs being lost in process and parts rusting .... and nobody is held accountable. Missing parts are robbed from one job to ship another. When the oil patch slows down and customers can shop around for goods and services instead of a quick one stop shop that can provide everything, NOV, with its bloated corporate overhead and losses due to mismanaged manufacturing, will crash.