Pros
All the classic "startup" perks - awesome offices, free catered lunch, unlimited snacks and la croix, a bar in the office, events like trivia/booze/beer pong, etc. A ton of people here are so friendly, talented, smart, and driven, and really want to do their best work.
Cons
Like another review stated, "PayPal with ping pong." Becomes more and more like PayPal every passing quarter, both culturally and in terms of management/goals. These are not positive changes. The bigger Braintree gets, the more the company tries to hold onto this idea of being a fun, small company with its own separate culture from PayPal. This just isn't the case. People used to hang out at the office after work, form friendships between departments/teams, etc, but not anymore. It's gotten cliquey and competitive. Managers have minimal manager training. There's almost no recognition for good work (especially when it comes from non-Product teams), only for early hires who are still around and have, seemingly by default, become team leads.