As one from HK, of course, I can have a 'better' comment on Cantonese Dim Sum restaurant.  Even I am from HK, I never tried Tim Ho Wan for one simple reason - it used to be a small shop and now expanding crazy and also regionally (to Taipei, Singapore).   This is also a sign of deterioriating quality against the speed of expansion.  To my surprise, there are a lot of positive reviews but I can only say from my first try, it is definitely just so-so Dim Sum, there are much more better Dim Sum shops in HK, well, maybe Dim Sum is a considered a rare specialty in Singapore so people just ranked them high.  Sorry, it is just plain so-so.  The portion is small, the taste is plain, the fried rice is not HK style (it added with a bit of garlic).   I understand the need of localization but I am a fan of respecting authentic and traditional recipe so sorry, this is not my restaurant and I will not come back again.  

As normal Singaporeans do, this one was always with a long queue when it first opened.  Now the hype is over, we finally tried the first time.  
We ordered a creamy cheeseburger, chicken burger and fish burger, set with curly fries and root beer float.
I must say, I am completely surprised by the so-so standard of the food (and why people will queue up in the first beginning).
The first deadly sin is - my beef burger is COLD, okay if not cold, then room temperature.    Well we did wait for 5-10 min to get the food, and I thought it was meant to be freshly made.   I can only say all the burgers are nothing worth to try again, or to recommend.  The curly fries are crispy, but that's all.  Root beer is the signature, so I will say is okay.
Overall, this only worth to try for one time only.  

I have been in F&B, and I definitely know the quality of buffet food will be inferior.  
So here, it looks like there are plenty of choices, but actually not:
- sushi and sashimi - only 3-4 choice??
- fresh cold seafood - maybe the most attractive in the whole restaurant - and one rare selling point is they have fresh oyster
- american - only pizza and grill pork, not steak.   
- tempura - 3-4 choices
- japanese grill - mainly selling salmon head - no wing no other meat
- satay - yes, typical beef and chicken
- wok fried - too many veggie but lack of meat
- long boil soup is good
- chicken rice and laska.....no nasi lemak?
- desserts - kacang, icecream, waffle etc.

I can say this is definitely for quantity, not quality.  

Not worth trying again.