We have just spent 3 weeks in unit E21 at the Kona Reef condos. First - the good things about this unit. Check in is a breeze. You have everything you need to let yourself in without having to check in with someone else. Very nice. The location is really good. Close to Kona town, it's only a little over a mile to the pier at the end of Ali'i. In that mile there are restaurants, shopping, and the public market. It's very convenient and you don't need a car. There is also a small beach next to the complex so you can have toes in the sand, again, without a car. The unit is very close to the gate to the pool and to parking, in the garage or in the upper lot.
The unit itself is well appointed. The furnishings are in good condition and the king size bed was comfortable. The kitchen is very well stocked with lots of dishes, silverware, glassware, pots and pans, bowls and a very good set of Henckel knives (unusual in a condo). There are also spices and a few other things that probably change with every guest but, by and large, you won't have to buy the basics.
There is a closet with beach gear. That may vary, as well, but we found some snorkle equipment, folding chairs, 2 beach umbrellas and beach/pool towels. And lots of books if you need something to read on the beach.
The lanai is the place to spend your time. It has a nice view of the ocean (not full on but you can watch the surfers) and it overlooks the pool and bar bq area. Because it faces south, you get the morning sun but it is shaded in the afternoon which makes it very comfortable all day without heating up in the pm. There is a conch blowing ceremony every day at sunset. A nice island tradition.
Also, having a washer/dryer in the unit is a bonus. Not all condos have this.
On the negative side: While close proximity to the pool and parking was convenient, it also created a certain amount of noise. People right outside your bedroom window with rolling luggage and loud voices at very early hours woke us up several times. There is also a very bright motion sensor light above the pool gate and right outside your bedroom window that comes on and lights up the room, even with the shutters closed. You are also quite close to Ali'i Drive which can be quite noisy at times. If you are light sleepers, this could be a problem. Also, be aware that while there is an elevator, it stops inbetween floors so you do have to negotiate a few steps up or down to get to your door.
Back to the positives. Marco is a very good host. I had to call him a couple of times and he was quick to resolve the issues. Both of our issues were not his problem - he just got them solved for us. All in all, we enjoyed our time in E21 at the Kona Reef.