I've been playing with PPV for the past year, and I must say, I don't like Media Traffic. I just never got profitable campaign in Media Traffic. I would say, Lead Impact is way better than MT. If you have more money, I suggest you try TV. Hope that helps!
I've had bad luck with Media Traffic, lately, but I'm not PPV expert. They were good when I was using htem last year, and as I used them lately, this year, I did not do well. I've also seen a lot of people on the forums saying their quality of traffic has gone down this year.
If you are serious about CPV, get on with Traffic Vance first and foremost. After that, you can get on with maybe 2 more to cross test. Others may suggest good ones at the moment. Media Traffic does not appear to be as good as it used to, but I too would be interested to hear if anyone is doing well with them, still.