I have never ever had a fourth-year medical student beat me to my room in the morning and set anything up beforehand, and I've worked with a lot of medical students. This means I don't expect that from any MS4s, and I like my room set up a certain way every single time so it might be more of a hindrance than anything else.
A couple of things I have noticed about excellent medical students vs. "okay" medical students is that the former tend to have a willingness or eagerness to learn, and they always have a high degree of emotional intelligence--this means knowing when to ask questions and when not to, when to offer help and when to stay out of the way, when to argue with the resident in front of the patient about the diagnosis/treatment and when not to (i.e., never), etc. I don't know that the latter trait can be learned. I can think of 3-4 MS4s this year who rotated with us and had these traits, and I really hope they match to our program.