I've been here twice in a span of three weeks (with two different friends on Nov 21 and Dec 08).
The first time I tried Onnki Donburi, it was for dinner and the waitress explained that their weekly donburi changed every week, so I opted for the Gal-B one (Korean Kalbi). It was super tasty, but probably a bit salty because I remember being pretty thirsty afterwards. Overall, it was good and I didn't expect any less.
The second time I went was for lunch and I really wanted to try the Salmon Lovers bowl... but... they just sold out right when I was going to order. I went with the Buta Fire bowl and, while it was good, I think they added too much seasoning because an hour or two afterwards, I was extremely thirsty (can't tell if it's because it was a bit salty or just the fact it was a spicy dish -- I did have about a cup and a half of water while eating). The heat is just right -- it's one of those bowls where it slowly gets hotter with the more you eat.
Just some comments:
- It's a bit more spacious inside than I thought but seating is still a bit limited (you either sit at the bar and watch them build your bowls or at the back with bar stools). There's a coat rack near the bathroom for you to hang your jacket.
- The first time I went, the waitresses would refill our cups with water. The second time I went, I was informed that water was self-serve near the entrance. Not sure what happened with that to make them change to self-serve, but it's no biggy.