My inlaws lived there for 20 years. Great place, they were very happy. I've been there a couple times for short stays and loved the place. I'm a golfer so two courses on site was heaven to me. Great "downtown" area with indoor/outdoor pools and nice gym. Tons of activities.
As to not filling up, I know that originally was not a problem and they were sold out. They keep expanding though so I can't speak to how it is now. I could ask my FIL he still has friends there.
They added a new section of less expensive homes, maybe this is what's not selling? I've never looked into the financials but just as a place to live and enjoy the amenities I wouldn't hesitate. One downside for me was the surrounding traffic. Seemed like any venture outside the community was a long trip. Not that there wasn't stuff close by, just that traffic was so bad.
If there's anything else you want to know, let me know and I'll ask my FIL.