I stayed with a student host. The one who I spent the night with had to go to an activities meeting for one of the groups he's in, so I spent a few hours with another student. Both seemed to really enjoy the school.
My overall impression of Sinai was very positive, and I can definitely see myself there and happy for four years. It is hard to pick one thing that makes the difference as I've visited 9 schools, so am usually only left with a general impression of how I felt I'd fit. However, a few of the things I like about Sinai are as follows (note: I am not implying that these attributes are exclusive to Sinai):
1. Location - manhattan, one block from the park ... I mean come on! What more could you want?
2. Classes start at 10 am ... perfect for me.
3. True Pass/Fail ... no honors or high pass until year three.
4. The apartments. They are spacious, nice, cheap, and I am looking for a med school where everyone lives in the same place. The better to get to know your classmates.
Hope that starts to answer your question. I'm sure there is more, but nothing that I can think of right now. However, if you have any specific questions that I may be able to answer let me know.