I worked for Convergint Technologies for around seven years. It is a solid, stable company which is growing into international markets with over 1,500 employees. The org chart is very flat and access to management is fairly open. There is a strong set of stated values, so be prepared to bring your A-game.
Convergint tends to think like a small company when it needs to think in terms of growth but that is slowly changing as the management changes. Probably the best thing about Convergint is that if you do your job, you shouldn't have to worry much about job security.
Convergint is a great company to work for; however, the Lanham office is not like other offices throughout the nation. They are staffed with wonderful, smart people that have the desire to do their best work, but management will try to work you upwards of 95 hours a week while on salary. I don't mind 50, maybe 55, but they want more on a consistent basis.
If you're not a friend of the main crowd, manager, or have some relative who has some pull with them, you're never going anywhere in this office.