Pros
You will learn a great deal. You will work with some very smart individuals. You will learn to work efficiently in a quick paced environment. Salary is comparable to other firms. Benefits are comparable, if not better than other firms. Bonuses appear to be based on merit, not length of time with company. You will have a great deal of work which will make the day go by faster.
Cons
You will not be able to showcase any talents. You will not be utilized to your fullest potential. You will be judged based on management's personal preferences. You will not be respected for the quality of your work. You will deal with lots of pettiness. You will need to have a thick skin. You will need to realize that promotions are not based on merit, so if this is your motivation, you will not thrive. You will have to watch your back.