Great place to stay! The comments about the noise from the utilities are a bit overstated. You can hear them mostly in the entryway/kitchen, but don’t hear them much from the bedroom. Also it just becomes white noise. As others have noted, you will have a couple flights of stairs to climb past the elevator. But it wasn’t a big deal, and you get to be in the penthouse!
The hotel amenities were great! Nice pool and jacuzzi and a nice restaurant which you can bring your own booze to (I think they are doing that for the time being until they have their liquor license). Plus the location in Waikiki is nice and central. Quick walk to beaches, bars, restaurants, and everything else.