Pros
Everyone at the company cares about the people they work with. It starts at the top with a management team that honestly cares about the quality of the experience that employees are having and it flows throughout the organization. There is no us vs them, everyone is pulling in the same direction to build something great and they do it with empathy and a recognition that we are all people first and employees second. Of course, when you have a culture so invested in the people who work there, you have to have expectation that everyone has the same level of commitment and at early stage companies, you need to be committed or you will stick out. If you want to do the best work in your career with people you respect and be part of something exciting, I think Thanx is a great place to do it.
Cons
You have to work hard to experience success. It's not a lifestyle job. If career is important to you, you will find like minded people. If you want to pay the bills, there are easier places to go.
You have to be a self starter. There is an expectation that people will understand the goals they need to achieve and drive themselves to get there, they won't hold your hand.