Pros
Good exposure to processes and methodology. If you haven't worked for a large IT Services organization, then you will get good learning here. Good opportunities for working with global teams and clients. The clients are mostly the top ranked companies in the world. If you are good at your work and have great communication skills, there is good opportunity to travel for projects.
Cons
Atleast in india delivery centers, too much politics - especially for promotions & travel opportunities. Very project-focused culture. Once you've changed projects or DU then networking with colleagues & seniors becomes rare, If you're a good performer at TL-AM level then the DU leads sometimes try to keep you at that level so as to not lose you via promotion to other DU's. If you're in a long-term project then work becomes monotonous after a while and asking for project roll-off is discouraged. New joiners given much higher pay at same level as old employees.