Pros
The guys are cool. Music playing all day. Free soda and coffee. Open-office, but not a lot of pressure. It's a job. If you just need a job - it's fine to go there. If you want a career - avoid it. It's a dead-end job, basically. If you have a family, and are ok being paid 10-30% less than other company would pay, but having to only work 40h / week, it will fit you.
Cons
Some of the stakeholders / founders (not sure which one of them should be blamed) do not keep their promises (that directly affects you, such as salary, benefits). In fact, other than salary, there are no real benefits (maybe soda / coffee / cookies / snacks as they say and all employees act as they would agree :D ). You can use their insurance plan, and maybe they'll pay, say 50$ and you'll pay 50$, but that's like pennies... They introduces 401k plans, but there is no Employer matching (probably better to keep your money to yourself, invest them in something). Everyone says the new office is so cool, but for me it was a huge downgrade from what I had at my previous company. No clear career path for anyone, mainly because most teams do not have a team leader. There is also a lot of technical debt.