This place does well because Tremont needs an ice cream place, and people like to eat ice cream in summer. The ice cream itself is nothing special, and the shop doesn't have anything that really makes it distinctive. The people are only somewhat friendly based on the few times I've been there.
The great part is how inclusive their food is. They have both gluten-free ice cream cones *and* vegan ice cream. What a haven for the lactose/wheat intolerant! :)