Avantages
None I can think of except that they'll hire people fresh from college with little or no experience and that they offer a decent pay rate and good benefits for new hires.
Inconvénients
They lie, cheat, and ruin good talent and their way of doing things doesn't make sense. I was told that my relocation expenses would be paid for. They weren't. I relocated to Cary, NC for the training and was forced to move to out of state at my own expense for a project with one of HCL's clients. HCL never reimbursed me for my relocation. They place new hires into a random technology that they don't know they're going to be placed into until after 2 weeks into the program. Also, they hold new hires back on their first payday so you may be a month without a paycheck. After training, you may be benched for several months before being placed onto a project, which keeps you from getting any hands on experience and learning anything. Also, they'll hire people full time without having a project lined up first and let them go if they can't find a project for them. Also, communication is a big problem since home office is in India and since you may be on a development team where half of the team members are working offshore in another time zone and some of your coworkers and supervisors, both onsite and offsite, may not speak English very plainly.