first of all, congratulations for getting the two offers, that’s a great achievement!
Both are great choices and you cannot really go wrong with any. The answers to your questions would depend on the country you are considering; I will report below my experience as for the Italian market, other countries may be different.
- Office camaraderie: McKinsey is suppose to be more competitive than BCG internally; I did not experiment this first hand as I worked for BCG only, but many friends at McKinsey mentioned a very competitive environment, thus less internal camaraderie
- Ease of upward mobility and an adherence to meritocracy: in general terms, equivalent
- Breadth of case studies/client projects across different industries: in general terms, equivalent; of course specific countries may have specific focus. In Italy, McKinsey is doing more financial services then BCG; that may be a plus or minus, according to your interests. You should get an idea of the sectors covered by each company in your target country looking at the proportion of partners covering a specific sector out of the total
- International exposure: in general terms, equivalent. McKinsey has more offices worldwide, however I did not see a real impact from that on travelling opportunities at BCG
- Non-financial perks: in general terms, equivalent (unless you include MBA sponsorships as non-financial perks; I have included that point under exit opportunities)
- Exit opportunities: McKinsey has by far the largest group of Alumni; this gives them an edge on what you could do after consulting. In Italy, at least till 2011, McKinsey was also supposed to provide more MBA sponsorships, which could of course influence exit opportunities.
One thing I would recommend you to do to make a decision is to also consider the general gut filling you got talking to the consultants during the interviews, and in particular how they answered your questions at the end of the interview. There are indeed a lot of factors you will not have control on during your consulting experience (mainly which project you will do and which team you will join) that could influence the overall experience; if you felt a click for a specific company though, it is likely that particular environment will fit more with your personality. This could become far more important than all the other elements in the long run.
If you did not get a clear picture of the internal environment during interviews, you can ask to talk more with some of their consultants – they will very likely organize a meeting for you.
Hope this helps,