Pros
Learn about yourself. Culture is based on truth and honesty with a constant flow of feedback, which leads to a great opportunity to hear what people all around you truly think about you realtime and gain for a truer self-evaluation / opportunity to improve Growth opportunity. Company is very open to lateral and vertical movement...just comes down to your own abilities and desire to grow. My own path was from a part time consultant in technology to a full-time employee working directly for the CEO. Work with great people. Some of the smartest and brightest around, and a true caring that I felt transcended work.
Cons
Work-life balance. Job can be all consuming, very long days are normal, and leaving the job at the job is tough: you can find yourself thinking about the feedback hours/days later.