Pros
1. If you work very hard for 2-3 years, or lick boots of your manager, you will get an onsite opportunity. 2. Job security (they wont fire you if you are on bench, because they will make you work on anything they like even for experienced people). 3. Lot of benefits, but they will charge a little amount for that. even for parking you car/bike.
Cons
1. Very poor compensation, much below market standard. 2. They dont care about ur career, they will make you work on anything and that too make you work like a dog. 3. They fool employees to curb the attrition, they will initiate a US H1B Visa, will make u fill all the forms, but at the end, they cancel they application (about 50% of the total applications). 4. 3 months notice period. It is difficult to get an interview call just for that reason.