Like all the other AYCE sushi places in Montreal, Kuu is just fine. Not amazing and not horrible.
Large menu with lots of selection, fresh fish and other items, and usually good tasting pieces. That being said, it's really nothing to write home about.
Service is usually ok but I find that whenever we've sat in the upstairs section it's been much slower so try to sit on the main level if you can. Apart from this, I have no favorite items because they're all average, and neither anything I can advise you to stay away from. Go check it out for yourself - I don't think you'll be disappointed if your popping in for a casual no frills sushi dinner. Enjoy!