Pros
BAE is large and there is the potential to work on interesting and important projects. In addition they have a full suite of benefits and a large catalog of internal career enhancement training courses. Granted the benefits (especially) health care seem to get worse each year, but I think that may be industry wide due to the economy and the political turmoil surround that topic.
Cons
BAE is large and thus they treat their employees like any other large bureaucracy: You're just a number. . On the project side you combine the bureaucracy of a large company with the bureaucracy of your main customer (US gov't) and you end up wasting a lot of time doing low value busy work. Finally, the group I was in had some of the worst line level management I've ever experienced in my entire career. Almost all of them were good workers who were promoted above there level of competence. It seems personality and leadership ability were not considered important at this low level. I would doubt and hope this was not the case company wide.