It's been about 4 years since we were there. The location is GORGEOUS! Sites were large enough and level with full hookups.
On the downside -
It's in the middle of nowhere. Grocery store is 20-30min away. Sackett's Harbor is 45min away.
The side near the office is down-wind of the prevailing wind direction. While we were on the island, the algae from the lake would build up on the shore in that area, begin to decompose and smell like sewerage. The CG did their best at trying to keep up with it by removing it frequently, but it was a losing battle.
The only other issue is that during certain times of year, the bugs are atrocious. We were there in late August and they were awful. Not biting bugs at all, but thousands of flying bugs that would land on everything. Dawn/Dusk was the worse, not so bad in the heat of the day. We had neighbors who left their camper doors open all the time and I cannot imagine how they dealt with it.
Lastly, the restaurant/activity building was closed while we were there. No idea if it's open now. Pool was very nice and clean.
We were there before KOA took it over, so I'm guessing there have been many changes since. My suggestion would be to get a site over toward the Marina side of the island.