Well, not in Singapore, where you have plenty of properties of all chains. The only reason I tried Sheraton, was to give another chance to them.
Location is not very good, rooms are old, staff doesn't care/know about SPG programs, etc. The onlt catch was special rates cheaper than the rest, but these days many of other properties are already matching it.
Competition is the best medicine, either Sheraton Singapore corrects it or customers will run away. Even within SPG St Regis Singapore rates are almost as competitive as the Sheraton.

Finally, for your info we stay at hotels because we have biz trips. We try to find where you feel more comfortable and the point is safe hotel, clean rooms and well trained staff.

It happens that SPG send us a package full of promises and gratitude, but we don't see it happen (upgrades being among the benefit SPG writes most).