I've been coming here long before this place blew up, so definitely have been returning less often due to the long lineups. However, I have nothing but great things to say about the food here.
I had the spicy red miso ramen, their signature menu item. In the past, I've always gone with the shio, but this is definitely my go-to now. Unlike other ramen, the chefs stir fry the vegetables under high heat before adding the rest of the ingredients into the bowl. This releases the fragrance and flavour of the vegetables into the broth! The noodles are also some of the best I've had in Toronto - they were bouncy and had great texture.
The only gripe I have about Ramen Isshin is the tiny seating. We were seating in the middle of the restaurant, and it wasn't the most comfortable time putting away your coat and bag in such a small space.