Vantaggi
You'll be building good communication, since mostly onsite based projects are been taken to provide the support and services. The only big advantage is that they don't fire you. You can work as long as you want.
Svantaggi
Mostly Support based projects are there and no development projects. There is no scope of learning new things or technologies, since the projects are old and use old technologies. (One might feel stuck!) People inside projects are very rude and understands you as there slaves. On the time of rating , some people take out there personal grudges and gives you less rating. Poor Work life balance, with high mental torture and pressure. The management is also not good. TCS usually hire the experience persons but only some have good knowledge based on there experience. (rest other mostly comes via reference) The salary hike provided is very low as compared to other companies. And the worst is 3 months notice period.