I think they have the potential to be good if they were way more democratic, but they're never run that way.
When I lived in a townhouse that was part of an HOA that had some nice things going for it. There were a couple tennis courts, a swimming pool, a communal garden, a club house thing you can pay to use, they regularly mowed the front yards and trimmed the front hedges and they would periodically repaint the fronts of the houses. However, while I was living there, the head of the HOA was a douche that kept misusing funds.
The house my sister lives in has an HOA that does literally nothing except bitch residents to upkeep their lawn.