Listen, no need to get defensive - I think mayo is "strong in GIM" because its a very strong program overall. I'm sure most of the mayo residents go into subspecialties, just as in the other highly sought IM programs. My point is that if fellowship placement was not a consideration, I would choose the place with the best training oportunities and I think mayo fits that bill hands down. I would rather be at a residency program where the sole reason for residents being there is to learn, rather than do scut.... and Mayo fits that bill as well.
However, if you're looking at getting into a highly competitive fellowship, it would be difficult to argue that the fellowship placements at Mayo are on par with those of MGH/Brigham/UCSF/Columbia/Duke, rightly or wrongly on the part of program directors. - Not that mayos's placements are by any strech bad, in fact I'm sure they're quite good, but not on par with the above mentioned. From my experiences on the trail, I've run into occasional people from Mayo, but the interview days are dominated by people from the above stated programs. So if you're planning on getting into a top notch fellowship, one would be wise to take this into account, and consider a place like Columbia for example, with a stellar fellowship placements, even if the teaching you get there and the quality of your daily work are vastly inferior to what you'd experience at Mayo. It wouldn't be worth it to make that sacrifice if you were not pursuing a highly competitive fellowship.
As for Fexo's comment, what a particular cardiology attending at the Brigham believes is irrelevant... what's more relevant is what the cardiology PD and chairman think. If you look at where the brigham cardiology fellows trained, you'll find that they're from brigham, mgh, hopkins, ucsf, duke, columbia, with a rare smattering of others -> This is not just due to geographical or inbreeding considerations, as EVERYBODY applies to these programs and even at the interviews you see few people outside of the above mentioned programs. Bottom line is that PDs take into account a "pedigree" of where you trained. Regardless of what they tell you in person, the actions of who they actually take speaks much more loudly. The same is true of the other top cards fellowships, though to a lesser degree than at Brigham and MGH.
*gigliing like a 12 year-old Asian girl* Just curious, why did you think I will be going to BIDMC and not the Brigham or MGH? 
