Article Marketing Automation (AMA) and My Article Network(MAN) are the same thing (MAN is a while labeled version of AMA).
I used AMA when it came out and I have a membership with MAN. I have been using it with a number of sites, multiple articles per site and truth be told, I don't know if the service really makes a big difference. Sure, you get some links, but it seems that a large number of the blogs in the system are low value blogs.
I also question the real number of blogs in the system. I think right now they claim to have over 15,000 blogs in the system, but I am not sure if that sounds right. I know last fall I removed my 800 blogs from the system (due to hosting changes and issues), and I wonder if other people did as well, since the distribution of articles fell during November/December.
It also made me laugh when they sent out a video in December showing the rankings that people were getting using their system. I think that they quoted 12 % of the sites were #1 in Google and 57% had top ten listings which they claimed they received using their system. But if you think about it, chances are that those sites are all marketed with other methods as well, not just AMA or MAN. I think most people would miss that fact (especially if you are a newbie), but realistically, we all know that to market a website properly, you would use various methods to do it.
All in all, even though I do use MAN, I don't count on it as my only marketing method. I see it as a way to get other links from other sites that I don't have to market on my own, so I consider it more of a bonus than a method I depend on. And when you consider that just six months of membership you could buy a license for LFE, you might be better off saving up your money and buying that tool instead - for me, it has worked a lot better.