I was on eHarmony for way too long. I only found one man I was willing to go out on a date with, and once we met, both of us knew we weren't anywhere near a good match.
Match was a similar experience.
I have a profile on okcupid and plentyoffish, but don't have them active all the time. There is an article on okcupid about why you should never pay for a match site...