* Very dependent on the defense cycle. After 9/11, the defense industry was booming. Lots of hiring, lots of money for interesting work. With all the budget issues lately (2010-2011), the first place to get cut is in defense R&D and in new projects. It makes sense: the government will pay for bullets and body armor for soldiers in Iraq, but they won't research new radar systems.
* Raytheon mainly does systems testing and integration. A lot of smart people get frustrated because the difficult, innovative work isn't respected. The genius who finds solutions to everything might not get compensated as well as the dummy that leads the test. If you like the research side, go work at MIT Lincoln Laboratory instead (although the pay will be about 25% less than Raytheon).
* Diminishing returns on compensation. Moving up in the company is mainly a function of age, not skill. Many talented engineers that start at Raytheon leave after 3-5 years because the raises are promotions are big and fast, but hits diminishing returns quickly. Those that choose to stay longer tend to be known as "lifers" because they are very unlikely to ever leave the company.
* Non-transferable skills. Programming is done on ancient language (military follows the rule of "if it ain't broke, don't if it"). All the processes and knowledge is very contained to the defense industry. Another big reason why people who stay more than 3-5 years become "lifers".
* Security clearance can be a pain, especially for people not born in the U.S. or people with immediate foreign relatives.