The people who would best be able to answer that question are people who want shops in Beverly, Danvers, Gloucester, and Rockport, which makes it incredibly unlikely they will be willing to answer the question.
So, to reiterate what eclark3 said, sign up with all the companies. Even if someone gives you a list of the 5 that have the most there they may not have the most there in 6 months so you'll need to find new ones again anyway.
There are reasons that a body stays in motion
At the moment only demons come to mind