Just came across this thread and it pretty much substantiates my experiences having been SPG Plat for a couple of years but seldom getting "promised" suite upgrades. That made me move from Starwood where I had vested a lot of years and points. Since becoming a Gold Passport Diamond last year, while I've not had suite upgrades that often on stays, it has happened more times than my overall SPG Plat record. This apart from the 4 confirmable upgrades offered each year, all of which were delivered with satisfaction.

As mentioned by the OP, there is also definitely a more positive attitude by Hyatt staff to their top tier elites. They express a genuine thanks for your business and go the extra mile to meet needs. I never feel I am a "freeloader" when doing award stays, the way I do at other groups.