I think there are good and bad aspects to 55+ communities:
1) Most likely your neighbor will not be hosting and parties that go late into the night
2) A lot of clubs/activities with a variety of interests
3) Home features that may be desirable if your health changes
4) Possibly a co-located assisted living/nursing home if needed later
5) the homes (especially available storage) seem to be on the small size (that's a good or bad feature), especially for the price
6) HOA fees could be high. Yes, they may take care of home/lawn maintenance, etc but I view this as being a permanent cash cow for the developer.
7) The pool of people who can buy your home later is narrow and you may be competing against all nearby sales of homes with the same floor plan
8) I have heard of many women in retirement communities who are extremely protective of their husbands and will shun any woman who is single/widowed (competition). This may be pretty isolating for the ones that are single. They may also shun a spouse who is younger. And on the flip side, I have heard of one community where the rate of STDs is higher than average (hopefully this is confined to those who are single only).
9) Some communities are for married couples only - and if a spouse dies, the surviving spouse is forced to move (and that's just what you need, to cope with grief and moving at the same time).
10) You may be limited in what you can do to remodel your home without community approval. So your place will forever be "Model 101".
11) Some communities allow residents to drive around on golf carts - and some of them have eyesight so bad that they can no longer legally drive (so watch out!)
12) Some communities may have a majority of the homes occupied only certain times of the year. So if you buy and live there full time, you may find yourself on an empty street for part of each year.
13) The community may have some "hotel rooms" available for visiting family - but on a first come, first served basis - and for a limited time. So if you have an extended illness or need a child to help provide in-home care, it may not be possible there.
14) You may find yourself in a fishbowl of gossip - and most likely a good portion of it is either completely untrue or has been twisted around.
15) People who need to step in and take care of grandkids (parents die, etc or military and on deployment) have to find somewhere else to live.