Pros
Raytheon is a large, diverse company with many different opportunities. It can weather the ups & downs of defense market by shifting focus to international or civilian business, etc. If you are interested in doing different things, you can usually find something within the company. It's hard to generalize with such a large workforce, but for the most part people care about their job, and try to do their best. The company offers industry standard pay and benefits - not the best, but not bad either.
Cons
Being a defense contractor, most programs are not dealing with cutting edge technologies. The company is very process driven, which stifles creativity somewhat, but allows for more consistent results. Corporate culture is slow to change and react to markets.