Easily one of the best place for wings in Toronto, especially if you like your wings spicy!
I have regularly eaten at duffs for about 4 years now and have never had any complaints. The service has been consistently good every time I have been there and the wait times are reasonable even when the place is packed.
It is a relatively small restaurant though and being popular, they tend to fill up fast on weekends and Tuesday nights (which is their wing special night) so there does tend to be ~20 min waits on those nights.
The food is great though, they easily have some of the hottest wings in Toronto and I wouldn't recommend the top 3 hottest flavours to anyone who cant take some SERIOUS heat. For those who don't enjoy clearing their sinuses and sweating profusely while eating wings I would highly recommend the "hot honey garlic" which is one of the tastiest wing flavours my friends and I have ever had. Their onion rings are also among the best; fresh, crispy and delicious and I highly recommend them over fries as a side.
Overall its a great place to go if you are in the mood for wings, more of a restaurant than a bar however they do have a bunch of TVs on the walls to watch games. Food is usually about 15-20 bucks a head and drinks are reasonably priced.