-- Good things:

Location. In the very central part of Tumon, more than walkable to pretty much anywhere. Located on the seashore, and it takes just a short walk down the stairs to touch the ocean. Hotel itself is positioned the way it gave very good view to the sea, no complaints at all.

Pool. The pool isn't too large, but it is very clean, nicely maintained, with rental towels and rental swimming tools. The water felt a bit too cool for my liking, but still, it was nice. There's also a chapel next to the pool with Yoga sessions, atmospheric and nice.

Staff. Everyone was friendly, professional, quick and just let me alone when I needed it. Not much else to say. There's also Japanese-speaking concierge which is, I suppose, a big plus for Japanese guests.

Internet. Surprisingly, WiFi in Guam is although widespread, but often of low quality. In Reef hotel it was good. Stable, fast and easy to connect.

Room amenities. The basic amenities, such as soap and such were good enough. There was even microwave oven and an ice maker in the walkway.

There's quite authentic Japanese restaurant downstairs, and chef seems to be Japanese, because the food there feels not much different to that eaten in Japan. Also, a 24/7 shop with tiny stuff to buy, although I found it a bit pricey.

The room felt very spacious and bright, excellent room. A special mention must be given to the quality flooring, which was bit slippery, but still pretty.

-- Things to improve:

The hotel is old, I understand that clearly and that is where all its problems stem from. The room never felt fresh, despite conditioning and air dryer installed near the ceiling. It was refreshed, but I guess it would be a bit stinky if it wasn't. You could literally feel it is a bit damp. Must be related to the wet climate of Guam too. Sometimes you could see the carpet rising from the floor with large bulbs, which isn't too pretty. Also, the air was bleeding from the closed balcony door, must be unnerving in the event of typhoon.
Besides, I did not really like the bedding. It was too soft, to the point when I felt sinking into it, and pillows were not too pleasant too. I'd say the sleep quality was average, but nowhere above it.

I had a comfortable room for 4 nights….no complaints at all. Clean, good bathroom with the customary Japanese toilet (many features!). Staff were friendly and responded to my few requests. Breakfast caters mainly to Japanese guests but still with plenty of western options……scrambled eggs or omelets, bacon, juices, rolls and toast served buffet style. Actually good value for this part of Guam.