Historically a tier-2 consulting firm, similar to that of Wipro, Infosys and TCS. More recently trying to re-badge their 'consulting' arm as being tier-1. How successful this will be only time will tell.
My recommendation would be that if your friend can get into Accenture, the Big 4 or boutique consultancies, that would be the best bet.
If they can't get into the above, Cognizant is the better of the other 3 listed above.