I had the all you can eat hotpot at HKYK for dinner twice in the last 2 months, and each time was a similar experience. I have no complaints about food quality, it was pretty good, although of a similar quality to other hotpot restaurants on alexandra road. Selection is quite large though, more than most hotpot places I have tried.
The main problem I have with HKYK is its consistently slow service. Both times I was there, every order took at least 30 minutes for the food to arrive. Since there is a time limit (like at most hotpot places), the most I can order is 3 times. Also my third order always gets cut off, as in they have no problem giving me exactly what i want in the first two orders, but my last order they decide not to give me 1/2 the stuff I ordered. They also have all you can drink pop or plum juice for just a dollar (or two?) more per person. This is not as great as it sounds, since they almost never come around to refill the drinks. I was not full when they gave me the bill, because the food came so slowly.
Lastly, both times I was there, my bill was incorrect, which seems tough to do since its a set price per person and the price of drinks. It was changed quickly when mentioned, this was the only fast part of their service.
The service ruins it for me, and I will not return. I gave them two chances, as service is sometimes a hit or miss in restaurants. To take 30-40 minutes to put raw food on a plate is too long.