congratulations!! They both are great B schools, I prefer CBS because of it's location. Considering your future career plan, I think CBS better for PE/VC while MIT better for your family biz. Good luck!
Tech VC (not sure about energy): Sloan leads CBS for 100 years.
PE: Both not strong enough for mega fund. CBS has slight advantage due to NYC location for MM fund.
Family business: CBS should have better brand name in most non-US countries (esp Asia/EMG).