I'm a 2nd year MBA at Sloan, II'd shed a little light on some of the questions here. I'm happy to see that several applicants have had positive things to say about their interactions with Sloanies.
I would definitely say that the social skills of the student body contradict the stereotype. People are outgoing and quite expressive in class. Classes are a mix of case study, lecture and problem sets, and there is a lot of teamwork.
As for the alumni network, I've spoken with a few alums so far and they've been fine. One thing to keep in mind is that Sloan only used to graduate about 100 people a year, so its alumni network is somewhat smaller compared to places like Wharton and HBS. Currently, there are about 350 people in each class, but still there are other schools with more sizeable (and as a result visible) alumni networks.
Sloan students are indeed allowed to cross-register in two courses outside of Sloan (either at other MIT schools, or at Harvard or the Fletcher School at Tufts). Anecdotally, I think most people who cross-register go to the Kennedy School at Harvard, but I know folks who've studied at HBS and Harvard Law.
Economics pervades the curriculum at Sloan, and most of the faculty's backround is in econ, I would say. There certainly is a quantitative strength, but it's not all the school has to offer. The school's research strength is fantastic, and we have the chance to be exposed to this in more than just a superficial way, such as in class or during the new Sloan Innovation Period, which is a weeklong break mid-semester during which profs can share their work (and one of Sloan's core competencies) with the community. Overarching all of this is the emphasis on making these insights actionable. There are consulting projects with local firms built into the curriculum, and people are very serious about applying what they've learned, as well as contributing experiences gleaned from past work to class discussions. Research should inform practice, and at Sloan it does.
The workload is challenging, but that's what we're paying for. I have a humanities background so I may have found it slightly more challenging than others, but it has been worth it. I'm very happy with how far my business acumen has come over the last year. And I'm happy with my summer internship. | 
