We go to HKYK so much that the hostess recognizes us and makes small talk. We've been there for dim sum, late night dim sum, and hot pot.
The dim sum at HKYK is pretty standard fare, and you can expect good but not top-notch quality. They also have all day dim sum, so we often go in the evening after work. Not everything on the menu is available outside of regular dim sum hours, but you can still get all of the main items (hargow, siu mai, etc). It should also be noted that HKYK makes pretty great congee. We brought some friends once and tried the beef congee. It was cheap and they loved it.
HKYK has AYCE hot pot in the evenings (maybe weekends only?). It is a good bet for hot pot as it has fairly fresh ingredients, and a pretty big selection. We love their shrimp balls and deep fried bean curd skins. Their satay soup base is also delicious.
Service is usually decent, but not exceptional. If you mind waiting for your food, try going a bit earlier or later (not 7pm on a Sat). They do take reservations but you may still have to wait a bit at the door. Due to the size of the place and number of tables, the servers sometimes forget about your request because they're usually bombarded with requests as they walk around. It hasn't been a huge issue for us. We've just gotten used to asking several different people to make sure it gets through.
The thing that keeps us coming back is the convenience. Because the restaurant is so large, it's easy to get seated even on busy weekends without too much wait. Being able to go for dim sum at any time (not just before 3pm) is also great. Overall it's definitely worth a try and is one of our favorite places in Richmond.