Pros
Extremely nice colleagues. Very good working environment. Good challenges and some possibity of growth. It all depends on the sub-company and the specific project on which you end up working for. Good employee treatment, human relations with managers, and some benefits (included variable bonus). Nice company events, and if interested in the business part, many different customers around the world, with some possibilities to travel for work.
Cons
Of course there are. First of all the distinction between internal staff and external/contractor resources is very bad and creates a negative atmosphere. Furthermore for some projects the situation is terrible, and there is a discrete mess, as scarce planning and hard working days to put hands in badly designed software, maintained until the last possible drop of life, and the last buck taken from the customer. In some other cases the challenge can really decrease, due to reduced budget periods, in which there is small amount of job to do. In these moments the motivation can go really down, and the perception of growth can disappear.