As a matter of personal experience, I find that SPG Platinum suite upgrades occur at a very high rate (including all upgrades, even those obtained only after being politely persistent at check-in or after the day of arrival). I am aware that this is not the experience of many SPG Platinum members who post on FT and can only suppose that the difference is due to my travel patterns. I seldom travel in North America and do my best to avoid peak travel periods. It seems that people’s success rates with SPG Platinum vary widely.