We spent eight days at Kai's studio upstairs apartment. Hale Kai is a down-home property with lots of local flavor. Its greatest asset is its location, a short walk to two historic spots, one of which is good for snorkeling. We loved walking to the small beach to watch the sunsets. We were usually the only ones there. You can hear the surf from the apartment and there are lots of birds that give it a real tropical feel. It's definitely a lot different (better) than a sterile box hotel.
We got off to a bit of a rocky start upon arrival not being able to find the entrance after dark, but things got a lot better over the next few days after we figured out the quirks to staying at Hale Kai. Here are our take-aways for future guests.

The name it goes by is Hale Kai, not Steps from the Sea, and there is a small printed sign on the metal gate to identify it (not visible from the street).
The front yard is dark at night and there are a couple of old cars stored in front so it wasn't clear at first that we were in the right place. Once you open the gate and walk to the stairs, to the right, lights go on and it is easy to see your way up the stairs. For first timers, ignore the no trespassing sign and there is a latched chain to open on the metal gate.
Even with the foam bed topper taken off the bed is pretty soft, as others have mentioned. We prefer firmer.
All the amenities are there- great towels for bath and beach, kitchen is well equipped, it's very clean, guide book is helpful, three sets of fins one of which is adjustable. I used Kai's and they were great. There wasn't a pair that fit my husband, but we rented some from Big Island Divers in Kona where they were inexpensive and super comfortable.
On the downside we found that the space consistently heats up a lot during the day and doesn't cool down inside, even with the fans and air conditioner going, until it cools off outside. It was not fun returning to this in the evening. Another reviewer mentioned that the cross breeze keeps it cool, but we didn't experience this. Maybe it depends on the time of year, we were there in mid-October.
One other negative was the shower temperature control which was finicky. We followed the directions carefully for adjusting the hot water, but just when you thought you got it right the hot water would fade out again and you'd have to readjust and wait for it to come back. Hate to waste water.
Kai has put effort into trying to make a comfortable space, but we're giving three stars due to these conditions.