Have stayed at all 4 downtown YVR Starwood properties. 1st consideration would be price. If you're using points then select either the Westin Grand (although Empress I recall you've been there) or the Sheraton Le Soleil. Both are smaller all suite properties with good service and even better rooms. The Wall is a tall hotel so be sure to plump for a high floor. The club floors are approx 25 and 26th level. As a platinum myself I have always had to ask for my upgrade at the Wall whereas the Grand, Soleil, and even the Bayshore it was automatic.
BTW am headed to YVR this morning and will be staying at the Grand.
Have a nice weekend in YVR.