BCG London vs. Mckinsey Milan

Prestige will be roughly similar, although mckinsey is a slightly more prestigious brand name BCG is very close and internally London/ NYC are seen as the most competitive offices due to lots of people wanting to work there. Exposure will be similar and it's important to note mckinsey has a global staffing model meaning you will work on cases from all over whilst BCG is more regional. 

Exit opps, I think this one is tricky. Broadly speaking, London is a much bigger matket and lot more opportunities in London overall. It'll be easier to recruit for exits in London if you're already in London so BCG has the advantage. However, there are far fewer MBB caliber candidates in Milan competing for the same exits. In London you'll have to compete with a much higher caliber talent pool, lot of people from good T2 strategy houses as well as top junior bankers and others competing for the same exits as you. 

Comp and living costs are higher in London so not sure which has the advantage here. If you're solely optimizing for career outcomes, my gut instinct says go BCG London all else equal. HOWEVER, all else is rarely equal. Please make this decision based on whether you want to live in London or Milan. Where do you have family and friends? Where do you have a better network? Do you have any cultural preferences both wrt to the people you met from these offices and the culture of the city and country at large? You'll be able to perform better and succeed the most Where you are the happiest so these other factors should drive your decision - NOT somewhat arbitrary distinctions of prestige