Depends on where you are in MA and how far you wish to drive. You'll get lots of opinions as to "best" because people are comfortable with who they have. You may have to contact a few, see who you and your child are comfortable with, and go from there.
In the Dracut, MA area - I prefer Marc Deschenes at Future Stars. My son also worked with Colin Lynch a bit - I know he's associated with the Granite State Showcase League and I think he's coaching at SNHU right now. In Southern NH, there's a following for Mike Jackson from the NH Grizzlies while others like Keith Bowen - not sure where he's out of now, but he coached Hudson Legion this year - so a little bit of Google will probably find him. There's also Nick Esposito who's working with the the Souhegan Valley Saints (Amherst, NH).
I'm sure this just scratches the surface, but those are a few that I'm aware of.