Pros
Black Box is a huge company and has all the benefits that go along with their size. However, most of the offices function as independent units of the company and maintain their ability to be nimble and adjust quickly. They also provide small company atmospheres where people really care about what is happening. While I am sure there are some "bad" offices, even two offices in the same area can be completely separate in terms of culture, people, tenure and attitude. Anyone looking for an accurate review of the Black Box office they are considering should pay very close attention to the office being reviewed because if the name doesn't match exactly the review means litte to nothing.
Cons
It takes a little longer than normal to get the specific benefit information when you start. They start benefits right away but it takes a while to get the details. The benefits are very generous though so it's worth the wait.