Interviewed at both and putting Case significantly higher than BU. I agree that BU has VERY good fellowship placement and has placed people at better places than Case in areas like cardio. I'm not sure how much of this is due to Case's history of offering out of the match spots in cardio to its residents and also it's hard to say how many people prefer to stay in Cleveland for family or other reasons.
I liked Case because of the PD, the residents, and the fact that the atmopshere isn't horrible. I did not get a good vibe from the BU PD and it seemed like a pretty malignant atmosphere. While it's in Boston, it isn't in a very good area of Boston. Also, you can live much better in Cleveland than Boston for the money. The only negative I see is that Cleveland isn't Boston, which offers some positives too (cost, car insurance).