Our stay at the Islands of Mauna Lani was simply wonderful! I can't really say enough great things about our experience there. The staff is extremely friendly and helpful, and our condo was stocked with everything we needed and more. They really go out of their way to make sure that your stay is ideal. For example, their check out time is normally 10:00 AM, but when we told them that our flight out didn't leave until 4:00 PM, they accommodated us with a late check out time of 1:30 PM.
The resort is gated, so we felt very safe and secure throughout our stay. Each unit has it's own garage, as far as I could tell, so you don't have to worry about your rental car getting scratched up while you're parked. There is also a private recreation center with a pool, whirlpool and grilling facilities.
There are several excellent restaurants nearby, but we also had a very fully stocked kitchen and propane grill available to cook our own meals. The Foodland grocery store at the resort is reasonably priced (by Hawaii standards), but be sure to register for their Maika'i card, which will save you about 33%. By the way, the staff at Foodland is also exceptionally friendly.
We had planned to snorkel at numerous beaches during our trip, but discovered that the semi-private beach at this resort was so perfect, there was really no need to go elsewhere. If you visit there, you'll understand what I mean.
All things considered, I can't imagine finding a better place to stay.