For in the Kailua area, the Sheraton might be a four star hotel. It is on the ocean, however there is no beach. Nice rocky shoreline and a very nice pool.
The Outrigger would be a step down from that, but is quite nice. There is a great snorkeling beach next door. The Bar at the Outrigger overlooks a large tidepool with resident turtles.
Other hotels are getting tired. The King Kamehameha Hotel is right at the pier in town. You can watch the cruise ships come in. There is a small nice beach on the premises. The Royal Kona Resort is what formerly was a Hilton, built in the 60's it's slowly undergoing renovations but is not close to a 4 star property, although I'd probably take it over the King Kam and save a few bucks.
Up north of the airport you would have the Four Seasons and Kona Villiage. Both of these are top knotch and often are mentioned in Best Hotel in the World lists. I don't really know the star system, but these are probably in the 5 range.
Further north up in Waikaloa (probably 30-35 minutes to the harbor -not the pier- where most of us launch out of) you'll find the Hilton and the Marriot. The Hilton is nicer and a nice place to stay if you have non-diving family - nice grounds with lots of pools. The Marriot I would put somewhere between the Sheraton and Outrigger in Kailua in quality. Waikaloa does have a nice shopping center centrally located.
Further north yet, say 45-55 minutes from Honokohau Harbor, you'd have the Mauna Lani, Mauna Kea and the Prince Hapuna. All are 4 star and up by my guess, have nice beaches but can't match the pools at the Sheraton and the Hilton.
Driving is wierd here. There is only 1 highway of note on the west side of the island, and it's just a glorified 2 way street. All hotels are at most, 2 turns off the highway. Hard to get lost, but the traffic is slow and frustrating at times.