Pros
The people who you interact with every day (aka the foot soldiers) are amazing, passionate people. Definitely love what they do, put everything they have into it. You have a chance to be free with your work ideas, pitch things that in a big company would never be allowed. Fast moving up the ladder (if you aren't cut) since no one is around for long. Work time is pretty lenient if there's not an immediate deadline, which helps with the random things life throws at you.
Cons
The management is a cluster. An absolute mess. No one knows how to tell a client no, and there is so much insider politics going on you'd think you were working in Congress. Some super long nights and days trying to complete a project on deadline, only to have another "fire drill" the next day. Complaints about working conditions, improvements to the system or ideas that aren't already being considered will be brushed off. Starting salary for the area is a joke. Some of the fun nights were really just excuses to stay later at the office. Telework days were often revoked with little notice for some deadline.