Pros
The real pro of RMS is the work/life balance: 40 hour weeks, flex-time, lots of paid holidays and decent PTO. Unfortunately, that's about it for pros. I really can only recommend taking a job with RMS if you need someone to pay for you to relocate. Take their (very generous) relocation package, work the year you'll owe them, then leave for greener pastures.
Cons
True fact: the 2 year retention rate of new hires is between 30 and 40%. I made it about 15 months. This is not a coincidence. I was specifically driven out by a hostile manager that was poached from a vendor and brought in to "clean house" but I would have left sooner or later on my own due to what a mess that place was: Heroic amounts of red tape, indifferent management and a truly depressing work environment top the list for me. Getting anything done is slow and inefficient and management is pretty well useless. Amongst management and a lot of the veteran employees, there's a conceit that Raytheon is the only game in town and if you feel otherwise, there's something wrong with you. The truth is, at least for RMS in Tucson, it's a dump. It's clearly well past its glory days and let's not beat around the bush: they're war profiteers who would sell nukes to North Korea in a heartbeat if the DoD would let them.