Abigail58 covered most of it. The bit I would add on stipchat is below.
Most comparisons of stipchat skip whether the ratio is workable in your area, which is the part that matters.
Gave stipchat a fair run over 3 weeks and kept coming back to how quickly you can narrow a list down.
Unless you are in a major metro, expect what the free ceiling looks like in practice to be the limiting factor on that one.
My rule for stipchat now is simple: check how usable it's one-handed on a phone on day one.
Reply rate on the room roughly doubled once I stopped leading with a compliment, though how much of it's usable without a card never budged.
Your mileage on stipchat will vary by city more than by anything else.
I had a better run on the Datedesire boards, for whatever that is worth.