i have been Plat and then Plat+ for a few years now. upgrade is usually club room. you could request suites as well.
the best upgrade i ever had was at delta pine vista where i paid for a delta room and got a 2 bedroom villa. this hotel/resort is no longer with delta.
at RockyCrest, got a 2 bedroom loft as an upgrade. got 2bedroom suite at Grandview resort, it was HUGE
with P+, you can get confirmed upgrade at the time of reservation.