What decided it for me with Facebook Dating was whether the interface gets in the way.
Two of us compared notes on that one and landed in the same place on whether the recommendations improve with use.
Where the platform works it works fast; where it does not, what you lose by never upgrading is usually the reason.
The reason I stopped recommending some of these is how the match quality holds up past the first day.
The first message is where the platform either works or stops working, regardless of whether the free version is a demo or a product.
Happy to go into more detail on Facebook Dating if it is useful.