Congratulations on scoring 2 admits and scholarship money! I think the Poll results reflect your aspirations for elite recruiting.
If you were willing to compromise that and settle for something more middle of the road (corporate finance, operations, etc) then with your work experience and with a Top 20 (Olin is #21) you can do well. It is still possible to get a consulting job of some level (probably even a cool one) but elite employment opportunities are usually centered around Top 10. Yale is a new entrant into that group but their numbers look strong.
On the flip side, there is no guarantee that you will get a better job out of Yale than out of Olin but odds are better with Yale, plus you get ancillary benefits such as better classmates, better professors, and traditionally a better alum network - that's what $80K buys.
P.S. I feel with Yale's non-profit and green tech focus you are likely to be connected with more projects happening in Africa than Olin. Also, don't forget about
Yale's loan forgiveness program - that could be a full scholarship in a sense.