I recently completed a 3 night stay here as Bonvoy Gold on an Amex FHR booking.
I booked a Garden View room in the historic building, and got upgraded to a 4th floor room at the Mailani Tower. Based on dummy-bookings on the website, occupancy on our dates was low, so I imagine this was a better-than-usual upgrade. The rooms were nice, but based on the view we had, you can understand why the higher floors are a different room category:
View from the 4th floor
The Mailani Tower provides nice laid-back mornings where you can have mimosas in the lounge before heading to Surf Lanai for the "real" breakfast. The breakfast voucher allowed a menu item in addition to the buffet. The $100 property credit was used for three days of beach chair rentals, which covered almost all the costs. The happy hour at night was generous with drinks, but I refrained from eating much at all there.
Late checkout was provided without any issues. Early check-in wasn't needed or requested.
The resort fee was not waived. However, the costs were charged directly to the hotel instead of FHR, so it qualified for a $75 Amex Offer at Luxury Collection hotels.
On the whole, I really enjoy this hotel. I know there are nicer hotels elsewhere, but none of them capture the Hawaiian vibe quite like this.