Pros
Some projects can be very interesting (but tend to be few and far between). Depending on what site you're based at you might find that you are merely resource to do any old task that has nothing to do with your skills. Pay is good. Work-life balance is excellent as the business is very flexible around working hours. It's unusual to see people working lots of overtime these days (but then maybe that's because we've all been burned in the past). The atmosphere in the office is pretty relaxed
Kontras
Little in the way of professional development - well, none actually. There are few training courses and little upward mobility. It's a highly political environment and those who play the game best seem to do well. Communication is all top-down. Senior management seem aloof and disinterested in the opinions of engineers. Very much a "them" and "us" tension between the executive population and the rest of us.