My friend: I was in Bain for 4 years and now I´m in McKinsey, so I´ll give you a straight answer:In both you will work a lot (and a lot means a lot!), you will have brilliant colleagues and many really challenging assignments.The big (if not only difference) is the approach:MK is much more theoretical. Big frameworks that look really good but sometimes do not work very well when implemented. Bain is more practical, in the sense that your objectives as a consultant are linked to the success or failure of your work after implementation.So, if you´re an academic go to McKinsey; if you like strategy and implementation, go for Bain.They are both great, so do not worry about prestige, salary, etc...Good look and good work!