I used to have Grundy and my agent changed me to Hagerty. I am going with a different agent who suggested American Modern. They were much more affordable too.
Most of my friends are using Hagerty and Grundy. American Modern has just recently started writing policies in Mass.

AM was 50 cheaper than everyone else for me i will probably give them a call when i get ready to switch and make sure everything is good with my modifications.

Grundy/Hagerty has no mileage restriction and AM does. Just an FYI.