I went there about two years ago. Didn't eat at any of the fine dining options on site.
Here are a few recs:
-We really enjoyed Roy's. I thought it was less than the onsite options, and the service/food was great.
-Bamboo was another great restaurant about 30 minutes away down the coast. The surrounding area is beautiful.
-Take the helicopter or plane for the volcano. We drove, it was an exhausting day.
-Check out the beaches nearby. Hapuna was awesome.
-Either buy/bring some snorkel equipment before you go, or go to Snorkel Bob's. Resort prices are outrageous.
We were pleasantly surprised at how much we liked the big island though, and would go back.