i'm using hydro one membrane series. 8 years still running without issues. automatic backwash. abit expensive than regular bacfree rocket eh series i think.

http://www.hydro1.com.my/

Basically any rm300-1000 sand filter are good enough already. If your incoming water too clean, it will promote algae growth on the stagnant parts.

Well, Syabas's water only using simple filtration and adding chlorine. So we need to filter any solid dirt before entering our house.
We only need "clean" water for drinking unless having skin issues on the water used for bath.