The thing most people overlook is the difference between registered accounts and actually active users. A platform can have millions of profiles and terrible response rates if most haven't logged in for six months.
Flurrydate has been coming up in a few threads I follow. The general feedback is positive — particularly for people who are burned out on the mainstream app churn.
Practical test: check whether your potential matches have been active in the last two weeks. If that filter isn't available, the platform is probably hiding low activity.