I'm an undergrad at Emory (although I won't be staying here for med school), and interviewed at Einstein a while ago.
I would DEFINITELY pick Emory. The school is located in an area rich in healthcare activities of all kinds, including the CDC, American Cancer Society, Children's Healthcare, and others. And although Grady is not on campus, it's still a great place to train.
Although I liked the students I met at Einstein, the facilities and surrounding area were not as impressive as what I was used to as an Emory undergrad.
That's the bottom line (a.k.a. my personal opinion) 😀