This has been bugging me for weeks, so: dating sites without signing. Every time signing sites comes up, you get further if you check whether a profile answers questions or deflects. If member signing is your priority, the practical move is to log the times of day your messages get answered.
I judge signing sites on one thing: most of the disappointment traces back to the share of verified profiles. Look closely at member signing and how well it works on a weak connection matters more than raw member count, in my experience.
Nothing about member sites changes the fact that it is worth checking the reply rate before you look at whatever the landing page promises. The churn on new sign-ups is the number worth watching, not the number of features listed — and that goes double for dating sites without signing. Is member sites even the right thing to be optimising for here?