Pros
You get to own and develop your own sub-product within MA's portfolio and drive development from concept all the way to supporting the customers when it is deployed. Intentionally a low-process company, No Product / Project managers, daily stand-up meetings and as a developer, you can get by with only a single meeting per week!
Working with Erlang/OTP is a bliss
Cons
Takes a while to get used to a low-process collaborative culture if you come from traditional agile development.
Team-work is only emergent as there are few official teams.