As a current Harvard student, I recommend you pick Yale. A lot of people at Harvard are cutthroat (personal experience -_-) and have a superiority complex about them. I've heard few if any stories about Yale being like that, rather Yalies really do seem to get along better. I'm actually planning on transferring out of Harvard to Stanford, but I'm also going to apply to Yale; we'll see how it goes. And by the way congrats on getting an acceptance on both, thats quite the accomplishment!