Originally Posted by horizontal

I think the location depends on what you're after. The Westin is great for visiting the Marina Bay area (including Gardens by the Bay & Marina Bay Sands), financial district and Chinatown area.

The Sheraton and StR are near Orchard Road. StR is in my view better located at one end of Orchard Road and near the Botanic Gardens. Orchard Towers is right around the corner which may be a minus to some. Sheraton is closer to public transport (Newton MRT), but not near much of note itself (apart from Newton Hawker Centre, which is a terribly overpriced tourist trap and best avoided unless you have a local friend who can help you navigate it). Again, not very useful since you'll probably take a cab; I've found it slightly easier to get cabs at the StR than the other two.

Upgrades vary - some plats have reported zero upgrades at all three. I've yet to be upgraded at the StR and haven't stayed at the Sheraton since becoming plat. At the Westin I've had an executive room but not a suite. But on average the rooms are much nicer at the Westin and StR than at the Sheraton, whether you're upgraded or not.

Lounge breakfast is better at the Westin than at the Sheraton. Both are fairly limited, but the Westin's lounge is nicer, newer, and has better food both in terms of quality and quantity. Both pale in comparison to breakfast at StR, which in my experience plats get free at StR even without giving up the 500 points. On the strength of this point alone I'd go for the StR if the price is about the same to