People will queue daily to eat their lunch at Rose Garden, simply because the food is tasty and plentiful. It's a real Asian version of a Viking meal, you can eat till you burst, if that is your thing. I usually just eat two dishes maximum at a buffet.
While the food is tasty, and the place extremely popular, the popularity of the place makes it feel very busy and everyone is sort of fighting over the food (this is something I find a bit tasteless), and you'll often have to move over because someone else can't wait until you've had your fill...yes, all types of society - you'll find them all here, and understandably so - the food is pretty good for what you pay, and the staff doesn't seem to have any complaints about any customers. People can basically do what they want.
So, if you want to bring your girlfriend for a finer dining experience, lunchtime probably isn't the best, I'd say...make it a late dinner and À la carte, and you'll be all set.
The staff is so busy that they can come off as a bit rude, but don't let that deter you from eating there, if you're a tourist and really hungry, you'll get your fill - eventually.