As for Ritz vs. Sheraton, here's what happened.

1. Checking-in
Sheraton: I received very nice and warm welcome from the front desk agent at 1AM. The bellman was very attentive and ran to me to get my bag immediately after he saw me coming into the lobby. He took me to my room explaining all the stuff.
Ritz: The front desk person was so busy counting credit card slips and did not even pay attention to me while I was waiting right in front of her at 1PM. I asked her if this is the place where I can do check-in, she responded, "ah, yea." But her face was still looking at these credit card slip copies. The bellman did not come to get my bag until I looked around and asked the same front desk person if a bellman was around. While the front desk person was doing my checking-in, all she was talking about was "If you would like to use Carlton Club (whatever the one at the top floor), you need to pay additional S$60. If you would like to have a marinaview room, you need to pay additional S$30." The bellman who carried my suitcase disappeared as soon as he left it by the door of my room.

2. Doorman
Sheraton: Every time my friend's car arrived at the entrance, they opened the car door for me and say "Have a good evening" or something and close the door for me. Every time I approached the main entrance door, they open that for me and ask me if I need a cab.
Ritz: They were standing, but not doing anything. Upon my departure, I had this carry-on suitcase pulling and I had to open the door myself. I walked to the taxi stand, then finally a guy (doorman) walked towards me.

For the money I paid, I would absolutely choose Sheraton over Ritz. Their bathroom was stunning though. I left a guest comment card describing my experience at Ritz.