Why did Keith Ferrazzi choose Deloitte over McKinsey after bschool?

I just finished up Never Eat Alone by Keith Ferrazzi in which he outlines how a relationship with Pat Loconto moved him to choose Deloitte over McKinsey after B-school. 

Keith explains that he was at an annual end-of-the-summer cocktail party for Deloitte interns and saw a, “big, gruff, white-haired guy who was holding court.” While the other interns kept their distance Keith went right up to the man and asked him who he was. The man was Pat Loconto, CEO of the firm. After a good conversation they both found out that their dads were were first generation Italian-American and had been raised by parallel principles. The conversation sparked a bond between the two that would last for some time. After finishing his MBA Keith was on his final day to make a decision about if he would go to Deloitte or choose McKinsey. He got a call directly from Pat Loconto who was pressuring him (in the best way possible) to accept an offer from Deloitte. If he accepted right there on the spot Pat was going to extend a dinner invitation to Keith for later that night in New York. Keith slyly said, “Listen, I’m still up in the air. But it would help if I had dinner with you and a few partners to get a better feel for what I’d be doing and where the organization is headed.” Next thing he knew he was at dinner with Pat Loconto and some of the Deloitte partners. Towards the end of dinner Pat started ranting about how the CEO of McKinsey does not know who Ferrazzi is and how he will get lost as just another number crunching MBA if he does not accept Deloitte. Like a pro Keith said, “Look, I’ll make you a deal. If I accept your offer, all I ask is that you give me three dinners a year at this very restaurant for as long as I’m at Deloitte. I’m in if you’re in.” Pat turned to him and said, “Great. Welcome to Deloitte.”