Vantaggi
For the most part, as long as you are semi-competent, employment is almost guaranteed. It is highly unlikely you will be terminated (unless there is an ethical violation or due to a lack of education/skills they can't keep you in management).
Svantaggi
Every upper management person in virtually every function is cut out of the same mould-- all a group of "yes-men/women". There's very little 'vision' or 'leadership' in this critical group. In many instances, the 'purpose' of a large scale work project is "because {senior mgmt person} wants to see this"--whether it adds any strategic value to the organization or not. If you're accomplishing all your goals/tasks, then the feedback is "good job, keep doing what you're doing"...which leads to zero career movement.