Completely different. Kona Village has a large resort footprint that blends perfectly with the local environment. The biggest issue with comparison are the rooms. Kona Village Hale are free standing separate structures, almost like a tiny home with a large private lanai and the resort offers more beach frontage.

If you want to compare the resorts on service, both have pluses and both have minuses, it’s very difficult to find consistency at any US resort, even the Amangiri gets bad reviews sometimes. Personally I think Kona Village offers more diverse dining options, whether you want foodie type dishes (we don’t), or prefer dining privately on your lanai with room service (this is a hidden secret for the best dining value at JV), or the paniolo buffet once weekly.

The spas are likely interchangeable. Kona Village wins on water activities, both free and paid. FS Lanai wins on land sports like golf and I believe has more tennis courts. The Hualalai course is only open to residents and FS guests so KV guests cannot use the course.

It all comes down to the type of experience you prefer, how much privacy and space you need, and the activities you enjoy. KV is easier to get to with nonstop flights from most west coast airports while Lanai requires an extra connection via HNL, although the flight is included with your room reservation.