The upper management within R&D is generally fine. A couple of big personalities may rub some the wrong way, but it's nothing that would affect day-to-day life. I really haven't seen any asshole/backstabbing boss behavior. You'll generally be heard out on things. There are a couple of lower directors that are difficult to work with (and for, I would imagine), but they're definitely the exception.
The culture is surprisingly cohesive and supportive, with relatively little friction between the functional areas. Again, there are a couple of difficult/obtuse people, but they're the exception. Possible that everyone has too much on their plates to spend energy on stupid rivalries and drama.