Pros
Since it's a private company, they don't have shareholders to please. This makes a huge difference in how a company runs things. They don't have to constantly chase the next fiscal quarter goals. As an employee, you will never fear lay-offs or pay-cuts. The company's decision-making is based on long term goals, which benefits the development teams because projects won't get cut just because they're not immediately successful.
Cons
The company doesn't have a lot of money to spend on employees. They're VERY stingy with the salaries compared to other tech companies. There aren't a lot of accomodations when traveling. They put you in cheap flights, and super cheap hotels. And they make you share a single rental car among 4 other employees who travel with you. Although the job feels stable, with the really low pay, all my friends who work at other publicly traded companies make 2x more than me doing the same work.