Short version:
I can't believe this place is still in business given that Star Walk buffet is just 6km down the road. The difference in quantity and quality between the two places is absolutely immense.
Long version:
The only "premium" foods that Mandarin has that Star Walk does not have are prime rib (low quality) and crab legs. The premium foods that Star Walk has that Mandarin does not have are: sashimi (Mandarin has a sashimi Nazi that will give you a plate with 2-3 on it at a time), lobster, crispy skin roast pig, Peking duck. The reason this comparison is important is that the non-premium foods are insufficient to justify the ~$27 price - if you go to a $27 buffet to just eat fried rice and sweet and sour pork, you're an idiot.
The demographics of the clientele is also very telling. Star Walk has about 95% Asian clientele; Mandarin has about 60% Asian clientele. Why is this difference important? If you walked into a "Mexican restaurant" in an area with a huge Mexican population and almost half the clientele are gringos, what would your conclusion be? What if the Mexican restaurant down the street had only 5% gringos?
So unless your sole goal of going to a buffet is to eat as much crab legs as possible, go to the one 10 minutes down the street. You'll thank me for it.