I'm a med student at Rochester and a bunch of my former classmates are now interns here. A few thoughts...
Overall, I think the IM program here is excellent. The program director is exceptional - energetic, approachable, and an advocate for residents. Resident feedback is often solicited and regularly used to improve the program. Teaching is very good and is a priority among most attendings, especially the medicine hospitalists and ICU attendings (I'm sure there are others as well, but these are the ones who come to mind). I have been impressed with the formal teaching here; the quality of conferences was as good as those I attended during a recent away rotation at a highly-regarded IM program. All are well-attended, although interns get paged out of noon conference with regularity. Residents of course work hard, but staying within the work hours regulations is not a problem and overall the program is very humane. In fact, many of Rochester's strongest IM applicants from last year ended up staying here because they felt this program offered training on par with some of the best in the country but in a less malignant atmosphere. There are plenty of research opportunities and those who want fellowships seem to be able to get them, though for fields like GI/Cards most stay at Rochester. I'm not sure whether that is because the residents chose this or it is their only option.
In my opinion, the one major weakness is a lack of autonomy. When you are on the medicine floors, about 1/3 to 1/2 of the patients are private patients, and their attendings often micromanage, leaving little role for housestaff other than copying down the orders. Though some are more hands-off than others, it is my opinion that a bit more autonomy would foster a better learning experience. In addition, often your only contact with the private attendings is their chart notes, which obviously makes it difficult to learn much from them.
The other major issue to consider about Rochester is the location. Upstate NY is certainly not for everyone. If you can handle the snow and enjoy living in a smaller city, it is a great place to be. It is also great for those who have families because housing is very affordable and the schools are excellent. However, those who are used to larger cities may have a difficult time finding enough to do here.
I hope this is helpful. Feel free let me know if you have any further questions.