Pros
Some people will talk about the culture as a "drink the Kool-Aid" mentality, and when you first join it will seem that way. But when you see the culture in action and find that management isn't peddling a lip service, you find yourself bought in wholeheartedly. I have been with the company for 5 years, I started as a Field Service Engineer and have been promoted to a support specialist. In my time here no one has ever mislead or lied to me about my responsibilities or expectations. I have known what was expected of me from day one. I came from an industry outside of IT, the company provided me training and the tools to learn and advance professionally. Management has always encouraged people to do what they are passionate about. In my time here management and my teams have always showed a genuine interest in seeing me succeed and fulfill my potential. Along the way they have given me the tools to do so, it has been up to me to get it done. SEI encourages there employees to be honest, upstanding members of their community by giving them days off to use toward community service.
Cons
I genuinely have no Cons to mention, anytime I have had an issue I have brought it up and we found a solution. It would take an extreme situation for me to leave SEI.