It's the right choice: MBA will considerably improve your chances of switching to MBB or top banks. However, a lot will depend on you: LBS/INSEAD will help you to get a first interview with McKs/Goldmans, but the rest is your job.You can leverage risks by: (1) switching to M&A or modeling/valuation group in ACN before MBA - it will give you additional exp and right network, so you will be able to apply to MBB/banks right from ACN and in case of rejection after MBA second time(2) passing CFA L1/L2 is enough to show the commitment and apply to banks without MBA; I have friends who switched from PwC to 2nd year analyst in Goldman&Morgan.Good luck!