I will reiterate other Yelpers that you will definitely encounter a line of some sort during the weekends. I recommend coming in on weekday evenings and if weekends are the only option, 1-3pm would be best, which was when we did this past Saturday.
While all AYCE spots are generally lacking in the flavour department, Gyubee is definitely one of the better AYCE barbecue spots I've tried.
As first-timers, we pretty much had every single meat and veggie on the dinner menu. My favourites would have to be the pork belly and beef brisket, as I like my meat to cook fast. I also enjoyed the corn and lettuce wraps. One thing I noticed was that almost every item was heavily seasoned with some sort of sauce, which did deter from the authenticity of the meat flavours.
The dessert game here was strong. The Melona bar does a great job of cooling your tastebuds off after a hot meal, and the creme brûlée is also not shabby. I saw a table of 3 order 8 amongst themselves!
Overall, better than what you can get in most AYCE places, especially at such a convenient location, so I would highly recommend!