Vantaggi
I've been here for more than 4 years and it's really a great place to work, though it depends on the team that you get in. For the North American team, timings are 2pm - 11pm which is great since you can do a lot of stuff before 2pm (like bank work or doc appointment) and we always leave by 11.15pm since we have a drop facility and everyone else shouts if we dont hurry up. Flexible timings and work from home whenever you feel like it (monsoons are when everyone comes to office for better internet speed). Culture is superb, mostly MBA freshers, so average age ~25 years. Promotions happen quite often. This is like college life again, but surrounded with smarter people. For NA, the field work is pretty straightforward and the managers in the USA are quite smart too! If you're good at what you do, there is the chance for Global mobility (some folks have gone to Shanghai, Poland, UK, US)
Svantaggi
If you're on the NA account, then workload suffers at different times of the year - mid Nov - Jan expect to work 11 - 12 hrs a day (maybe even weekends), Feb - April its around 3-4 hrs a day!! Pretty cash starved so dont expect any Diwali hampers, but the people, culture outweigh this. Salarywise (A senior analyst makes about 7.5LPA) you do find better prospects in IMRB, Fractal, Milward or IPSOS, but some of my friends there say they work ~10 hours a day! Life cycle here is ~2.5 years, coz you get bored of the work and after a point of time, salary matters more than the friends you make here - sucks!