Pros
Great mentoring. You get to work with some of the most brilliant minds in San Diego. Subject matter expertise. You work with talented Drupalers, who maintain dozens of modules and constantly try to push Drupal to its limits. Precision. You get to learn and appreciate the process used to bring simple solutions to complex problems. You will pick up skills like thinking of all the possible consequences of your code and how it will impact, positive and negatively the user experience and the site's performance.
Cons
Can't really think of any. Beautiful office space, comfortable furniture, excellent computers, freedom to work from home if needed and more importantly, a place where you really fit in and have co-workers you actually want to hang out after work.