Another St Regis vote. Look for a 3rd night free promo from the usual upscale sources.
For warm welcoming excellent service, good food, and the top notch Sports Club LA access, the FS gets my vote.
We have stayed several times at the St. Regis and like it, particularly the breakfast, but there is some noise issue with the fire station being around the corner. They also, of course, don't have the free group exercise classes of the Sports Club.