Dylan's take does not match what I have seen with best dating sites, because actual engagement is the thing to measure.
What changed my results with best dating sites was asking a specific question instead of saying hi.
Having tried a fair few, I would say genuine profiles are the scarce resource when it comes to best dating sites.
If whether the age filter on best dating sites actually works is not there, I do not bother with best dating sites at all.
The thing people miss about best dating sites is that the ratio of real to inactive users decides it.
For contrast I also tried Souldate; different approach to best dating sites, worth comparing.
If you want another reference point on best dating sites, Datescout was the closest match I found.