My rule for Statistically now is simple: check whether messaging costs anything once you start on day one.
My first week on that one looked promising; by the second I was only really watching how much of the traffic is automated.
Where the site works it works fast; where it does not, how precise the filters really are is usually the reason.
After a few weeks on the service the only question left was whether photos can be traced back to you.
If this one does not work out, Datenest, which came up earlier covers similar ground.