Pros
Job security. No external IP owner/Publishers. Most everyone is really friendly and easy to talk to. They also publish books which you will sometime get free copies of as they clear out their old copies.
Cons
Almost non existent planning ahead of time. Very reactive and not proactive. Leads often complain about the old boys club at the top that, can decide content needs to be completely reworked last second or that a new feature needs to be created just a few weeks before major submission. Juniors and seniors provided very little responsibility or training. Next to no hope of career or skillset advancement. As the team size grows bigger, instead of becoming more accommodating, they become more strict, control is more important than creativity. 90% of games are mods of their original game. Archaic engine and no desire from CEO to properly renovate and update it. All projects seem to be pet projects to appease the CEO on his interests. No desire from the company to be a competitive company in the industry as employers or game developers. They are happy that they make enough of a profit doing as they have been doing for decades.