Nats is fine for established people who have been around for years and have never shown a tendency to be dishonest. If you've been here for years, have thousands of posts, are open about who you are, and don't have a history of being ethically challenged or constantly defending those who are then I wouldn't think twice about joining your Nats program. And you would be one who I would trust. Some others? CCBill or Verotel is preferred for sure.
I've only joined one Epoch AP and it was last one I joined. I made some sales but I found it to be a mess and I wasn't overly impressed or confident about it. It's clear they didn't put much effort into the affiliate side of things and that's a shame.
On MPA and Mansion Productions. They have deleted or had moved entire threads of mine at GFY and in all probability have had multiple image hosts delete an image I have posted simply because it shows they had a shave module built into their old MPA2 program almost a decade ago. The decade old shave functions don't bug me as much as the attitude of the owners and their apparent recent actions against me for mentioning it do.
I believe this is what Mainstreamguy is referring to. I put the screenshot of the mpa2 shaving function in my sig a couple months ago after this image
http://tinypic.com/view.php?pic=2cebl3&s=5 was deleted on various image hosts multiple times. I removed the image from my sig after about a month. I've mostly moved on and only wanted to make a point that intimidating affiliates doesn't work.