I've been booked at all these properties -- a lot and over a good number of years. The Park Hyatt usually assigns most Diamonds to suites in the modern tower section even on points-only award stays. I've had dozens of my stays here -- way more award nights than regular paid nights -- and all of mine have been upgraded for free to suites. I would not generally recommend using a Diamond Suite Upgrade (on regular cash stays or on points+cash stays) at this property -- especially if you have any alternative use for the DSU -- since they default to suite pre-assignment/assignment for Diamonds.

The BsAs Starwood hotels are less likely to upgrade SPG Platinums to full suites than the Park Hyatt.