The reason I stopped recommending some of these is how precise the filters really are.
I gave POF about 4 weeks before I formed a view, mostly watching how much control you get over who sees you.
Where that one works it works fast; where it does not, how quickly you can narrow a list down is usually the reason.
My rule for the room now is simple: check how much of the base is genuinely looking on day one.
That is roughly where I landed on POF after a fair amount of trial and error.