Pros
You get to work on cutting edge technology. One of the best places to work if you are interested in airplanes or space exploration. Boeing is a big company and you can move around and get expertise in different areas of commercial airplanes or defense systems if you want to. Health insurance, retirement etc benefits are great. They pay 100% for education. Great place to get an advanced degree while you are working. With so many employees, the networking opportunities are awesome. A lot of recent college graduates are hired every year making it a dynamic place to work. I like seeing the end product of my efforts and it is an honor to be able to point to a plane in the sky in the future and tell my kids "I helped build that"
Cons
Since it is a big company, you can get lost and be "just another employee" if you don't pro-actively work towards your career. Pay could be better. The path to senior levels is not clearly defined. There are set rules about getting promotions and if you are an over-achiever, you might feel stuck in the corporate policies. For e.g. at a small company if you work really hard, you might get promoted a couple of levels or get a huge raise. This won't happen at Boeing since the managers have to follow company policies in these matters. No offices in some locations that young engineers might want to work in e.g. New York.