The best bagel in the world: just maybe. Montreal style is very different from NY style and I prefer it. The Montreal style is about the same diameter, but has much less dough, so there is a large center hole. The dough is also a bit more dense but with larger holes and slightly sweeter. Because of the different geometry, it cooks differently with a high crust to interior ratio.
Fairmount is one amazing business. The place is unassuming. It is about the size of a house and when you enter (anytime, as the place is open 24/7), the place is stacked to the ceiling with bakery trays of bagged sesame bagels. The sesame bagel is by far their best selling item. As you approach the counter you can watch the whole process from hand rolling the dough to boiling, seeding, and baking.
Order a sesame bagel with cream cheese plus a bag of fresh ones to take home. Eat the bagel on the bench out front and be prepared to be amazed. It may very well be the best in the world.