Just thought I'd share some numbers from my experience, so far. I ran an ad with Elena Petrova. Initailly the ad did not run correctly, when i contacted them indicating that I received no responses, they re-ran the ad and i started receiving responses the next week.
I received a total of 33 responses by e-mail, 1 response met some of my criteria but had some traits i did not desire, 6 responses read my ad enough to use my name in their response, 4 agencies responded with a generic e-mail, 16 responded with boiler plate responses (and did not even meet my specified critieria), 5 were scammers, and 1 clicked. So overall 2 were in the ballpark the rest were a waste of time and at best were using the shot-gun approach on their part since they did not meet the qualities i was specifically looking for.
But I really clicked with one, we've e-mailed each other daily for 3 weeks,and have started instant messaging for the last week.
FWIW,
Gman