Three things I would look at with private dating sites:
- if the match algorithm survives contact with reality — worth checking before you commit to private dating sites
- whether the age filter means what it claims when you test it against private dating sites
- if the reporting flow holds up under real use — worth checking before you commit to private dating sites
Building on Grant's point — quality of conversation beats quantity of matches.
The honest answer on private dating sites is that the ratio of real to inactive users decides it.
The thing people miss about private dating sites is that discretion is harder to get than people assume.
Everything I have learned about private dating sites comes back to one thing — who actually responds is the real number.
Having tried a fair few, I would say anonymity options are inconsistent when it comes to private dating sites.
For contrast I also tried Datenest; different approach to private dating sites, worth comparing.