I visited their office a few times to work on the quotation. They seem quite nice and the price is reasonable. After meeting a lot of IDs and contractors, I found their price is the cheapest among all.
One thing to note is Zhi Sheng is not very professional in the designing. You have to come up with your own design and tell them your idea. Because they're just contractors. That's why their price is cheaper than IDs.
However, I did not engage them because I found a cheaper one right before I was about to sign the contract. Not sure if this cheaper one would be better. Have to wait and see. My renovation will start this Sun.
Even though I don't sign contract with Zhi Sheng due to my VERY VERY tight budget, I still have good impression on them.