Pros
Truly friendly and collaborative work environment where people will actually invest in your talent. It's such a small company that you will actually get to know people across departments. Also, the people are all smart and hard-working. You're not usually at a place like this if you don't believe in what the company is doing.
Cons
Small company means less budget to do bigger things, which can be frustrating. Pay is pretty bad and you'll definitely get a raise wherever you go next. If you don't like your team or manager there really isn't an escape (though everyone is pretty kind, usually). Can get micromanagey.