Pros
Management is typically laid back and allows you to work independently without any micro managing. Projects are interesting and the corporate safety culture is excellent. Excellent resources; due to the large number of employees with various background and experiences, there is always someone who can answer your question or point you in the direction. Good sense of job security and friendly coworkers. Generally an enjoyable work environment.
Cons
Some managers are inexperienced in the projects they manage, having never done the actual work before themselves. This places field/work personnel in precarious situations that they are untrained and ill equipped to deal with. Some managers fail to manage whatsoever, and instead rely on field workers to work extra long hours and perform most management tasks, many times which are well out of the scope of their job title or pay grade. Relaxed management is usually a good thing but sometimes it can be "too" relaxed.
Long hours - 50 to 70 hours per week are not uncommon. Due to tight project budgets, management may restrict you on hours you actually get paid for.
No bonus so far and very difficult to get a significant pay raise.