Having stayed at the 3 SW properties in question, I would definitely choose the Sheraton Centre. My SW elite status has always been recognized, both as a former Gold and currently as a Plat. As a Gold I was always upgraded to a Club Floor room with Lounge access. Now as a Plat the room upgrade is to a suite with Lounge access. This occurs even on multiple night PL stays.
BTW, the Lounge is one of the better (and busier) ones that I've seen. Service and selection is great, and I for one, don't begrudge the hard working staff a token gratuity.