Avantages
If you're good at what you do, you can work less hours and still come out doing better since most of the people hired are unskilled since they want to pay dirt cheap salaries. Note: this doesn't always work as sometimes they will assign you to two clients at once (so that you work at night and never have time for family or hobbies) without extra compensation
Inconvénients
Low salary unless you're a favorite (usually involves being related or close friends with VP and above). Hard work will get recognized with cheap awards rather than salary increase or bonuses. You can be promised bonuses and never receive it as they will just dance around the questions and say "it's coming" for months (not sure how long it would have gone for since I left but I've heard it can go for years). If they get you a visa, expect even worse treatment. Constantly hiring inadequate people to avoid paying normal salaries. High turnover. I'm still in contact with the few people who have stayed but they say it hasn't gotten any better. No room to grow unless you're a favorite.