The Hawaiian Monarch is an older building. We stayed here for 2.5 weeks. It was a bit tricky finding the lockbox and lobby. due to a lack of signage. I had to ask for directions to the lobby and use Nobu's instructions to find the lockbox (no fault of his). The elevators are slow during peak times and are not air-conditioned, so it will be hot in summer and cold in winter. Lobby staff were quite friendly when we had questions (the lobby is actually and outside area, not enclosed inside the building.)
The apartment is small but cosy. Suitable for a single or couple.
Full sized fridge was a huge benefit as well as the toaster oven. The bed is a sealy posturepedic (I checked), so it is very comfortable for those with back issues. Wifi was a bit of an issue (kept dropping out), so have mobile internet ready. The tv was a bit of a disappointment. 6 channels of mostly news and game shows in the evening (with the occasional drama) when you want to relax after a long day. It did not feel like cable, but more like free to air. There was a lot of constant electrical interference on all the channels, so don't plan on getting too comfortable with tv. The shower was a bit odd. Being from Australia, we have 2 taps (faucets), one for hot, one for cold. This apartment was a single faucet you had to pull to turn on the water, then left or right for hot or cold. For the few issues we had in the beginning, Nobu was happy to come over and answer any questions we had and show how things worked.
Virtually everything you could need was included (though, bring your own umbrella for storm season, the one included was small enough for a child and a big storm hit a day or two after arriving). Air conditioning set to cool on 75F low in the summer, was perfect for sleeping at night. It does have a bit of noise when running, but I had no problem (and I'm sensitive to noise).
There are no black out blinds, so the sun does shine through brightly when it rises, perfect for those who like to keep their circadian rhythm in check.
Laundry is on the 5th floor (accessed by your door key) and requires a credit card to use (it does charge $8 initially to use the washer and dryer, but drops back down to the correct price after 3 hours. Weird system).
There are a few convenience stores nearby (ABC and Seven Eleven (711) and 1 restaurant (Tony Roma's). Everything else is a 20-30 minute walk to Waikiki beach (depending on your walking pace). There is a pizza place in the lobby area. The guy there makes a mean cauliflower crust pizza (check he has it at the time, it sells fast).
If you prefer quiet areas and don't mind the walk to waikiki beach, this a great spot. (just be aware you can still hear emergency services drive around with their sirens on from the 38th floor where we were). We did hire a car, but the parking at the Hawaiian monarch had bad reviews. The best places are either along the river over night and during the day (check the signage as parking spots fill up fast and certain zones and time frames are illegal), Montsserrat ave (always free street side parking opposite the zoo), or the public parking at the waikiki banyon (where we always park when coming to oahu.)