Match Match calls themselves "number one in dates, relationships and marriages," and they have the data to back this one up. It's pricey, but if you don't find The One in six months, they'll give you another six months gratis. Not a money-back guarantee, exactly, but an incentive to roll up your sleeves and join if marriage or an LTR is what you're after.
Bumble Bumble has really taken the dating game by storm of late. As far as online dating goes, at least. If you see someone you like, you reach out within 24 hours before the connection disappears. If you don't, you don't. For LGBT matches, either person can reach out before the connection is gone.