I've been to Kantapia numerous times since it is so conveniently located on Sherbrooke between McGill and Place-des-arts. Without the address ready in hand it could be easily missed due to its uninspired appearance. The decor is nothing outstanding but the place is always kept very clean and comfortable.
The first time I went, I got the seafood pancake which tasted more like burnt eggs than anything else. Turns out, I was unlucky and probably ordered one of their worst dishes. Later, I got to try their bibimbap, tonkatsu and kimbaps which were all very filling and reasonably priced. My favorite item on the menu is the spicy tofu stew which is one of the better ones in town. It's nothing you couldn't get in other cities with a larger Korean population, but great authentic Korean food is hard to come by in Montreal without getting away from downtown.
I have to mention that the staff is extremely friendly and helpful. One of them actually went out of his way to use his own data to help me find an address.
Great experience. I will definitely return.