CTS Bpo or TCS Bpo Operations which is best and why?

have an offer with CTS And TCS bpo division in Chennai, India, can anyone who is working in these companies or has worked ,or has friends working here of has any knowledge guide me /advice me as to which is best and the reason too.the pay scales are almost similar..i want to know the reasons in terms of individual growth and career, job security, Benefits, and last of all money..thanks in advance