Oliver Wyman vs. LEK

Hello! First of all, congrats on the multiple offers - I hope you're happy and proud with the results of recruitment season.

For context, I spent ~5 years at LEK straight out of undergrad so take my (perhaps biased) perspective. Outlined some considerations below, but as a pre-MBA associate, I doubt your overall career trajectory will differ much based on who you select. 

Geography - Globally, OW probably has stronger brand recognition and much larger scale. Assuming this is the US, OW probably has higher brand recognition. Office transfers within the US is pretty easy at the LEK though they don't advertise it - depending on the office city, your project mix WILL heavily vary.

Sector interest - I'd say most sectors, no material difference between the two in presence. I see OWs as the top non-MBB in financial services, LEK as the top non-MBB in pharma / biotech. If you don't have a strong preference / dislike for FS or Healthcare, probably not as relevant though.

Project type - LEK definitely has a larger mix of commercial DDs for MM PE. Without being dedicated to a sector, I'd guess >70% of your case time as an Associate will be on short 4-6 week diligences. Much less general corporate strategy than OW so most projects, even within specific sectors, will be analytical and external-facing in-nature (e.g., what is the opportunity for this market, rather than how should we design our company, what organizational efficiencies should we seek) 

Exit Ops - For pre-MBA exits, your project mix matters, but don't think it will exclude you from certain roles or companies. LEKs been sending more and more people to MM PE (both operational and investing roles). Guessing OW sends far more people to Corporate Strategy at F500s like a Capital One. Without a comprehensive search, an average exit from OW will probably be better than LEK, if you exclude investment related roles and also strip PhDs (who easily go into VC and the sexiest Life Sciences opportunities). Within both companies, career trajectory to hit post-MBA is pretty similar.

Culture - Beyond the "collegiate atmosphere" being in the office provides at LEK (they heavily advertise it, I have mixed thoughts), I always think about how LEK allows for a breadth of personalities to succeed. It helps they have a good mix of PhDs etc. and all the partners are generally less reserved than what you'd expect from someone at a consulting firm (self-selecting). Could be a function of minimal client exposure until you hit Manager (sometimes Consultant), but I'm a firm believer that LEK's project mix (analytical, in the office work) allows for reserved AND introverted people to shine and be recognized. Hard to say for OW, but for some other firms, this isn't the case from what I've heard from friends, who are exposed to clients very early and often. I don't think of this as a BIG detracting point for LEK - you're dealing with layers of internal leaders above you so I always considered the Partner group to be "clients" in a sense and good practice 

Quick and dirty explanation. Happy to chat more, either 1 on 1 or here (applies to anyone considering LEK or consulting in general)