In my opinion, nothing beats the blueberries from Maine. They have a wonderful true blueberry flavor. My daughter in law and I discussed this a couple of months ago and I bought some regular large blueberries from the supermarket and some from Maine (frozen) from Trader Joe's. There was a world of difference in the taste. The Maine blueberry pie blew the other one away.
Sadly, according to a guy in a town that bills itself the blueberry capitol of the world...and is oddly enough called Cherryfield...the Maine berries don't travel well, which is why they never reach market as fresh fruit.
When I have traveled up into north eastern ME in August you will sometimes find roadside stands, unattended, with a can for you to leave the money, selling local berries. What a treat!