John Stauffer (of Af-Am, English, and the head of Am Civ) directed my thesis. He gave me detailed notes on every paragraph I wrote, suggestions on content and style, suggestions for further reading, and endless enthusiasm. In the African Languages program, John Mugane will arrange for you to learn literally whatever language you want. These experiences were not anomalies. I have found the department to be the intellectually generous and extremely supportive.
From my own experiences, I don't agree with the idea that "if you are at Harvard that you are on your own." It is true that you must be extremely motivated. But, if you are not, then why are you attending graduate school anywhere?
I hate responding to the I-knew-someone-who-knew-someone-who-hated-Harvard-so-I-didn't-want-to-go-anyway-and-they're-really-a-bunch-of-phonies talk. Especially during admissions (and rejection) season.
But since there is relatively little information about Af-Am programs, I want to offer those personal experiences with the department and strongly recommend it. See the various speaker series and Du Bois colloquiums (see "events calendar" at http://aaas.fas.harvard.edu/news_events/index.html). See the breadth and depth of courses given on African studies (http://www.fas.harvard.edu/~cafrica/aca ... urses.html). See what's happening at the Du Bois (http://dubois.fas.harvard.edu/).
Negatives? They're not transparent at all about the admissions process. If you apply for one primary field, and they feel you are a better fit for another, they will not transfer your application, but ask that you re-apply next year. Also, if you fall off pace, no one seems to really go out of their way to pick you back up. In my experience, if you're down, they're down; if you fall off, you're wasting their time. I can't say that I disagree with that. But it is certainly not for everyone.