In response to peterparker's post; I thought it was a really relevant and interesting question. Here are some of my thoughts:
In short, no. I think that as long as you rotate in the same application cycle, rotating early (August) or late (October) doesn't matter. You either make a good impression or a bad one. The residents I saw all remembered me and the other rotators. I think very late rotations (November) probably could be helpful at the program where you're rotating, but its too late to get a letter for the ERAS application. Also, I've heard of people rotating a full year early (i.e. rotating in December 2012 with plans to apply in September 2013). That sounds crazy to me because you're making connections with residents who will graduate. Also, that's so early that they may actually forget any good impression you make. I didn't think that was a productive use of time, but hey, what do I know?
Other lessons I learned:
1) Your last interview will be your best, but that's true of everyone so I think it all balances out.
2) As you go through the interview process and see more and more programs, you start to learn what you want (and don't want) in a program. So what I did, is I went for a 2nd look at the programs I really liked, but interviewed early on - just to see if I still liked them (and I did!)
