Create users for important customers ("I have disponibilized a download just for you") and see them browse through your page and learn what really matters to them.
It is also the only one that offers a wide range of customization options.
The only reason I don't give 5 stars is because the support page is a bit lacking, I'd prefer a forum of some kind.
Definitely the right choice for anyone looking for this kind of integration. Don't bother paying for other options out there, I did try a few and regreat the money, should have donated all o it here.
I just don't give it 5 stars because the documentation is kinda lacking and because of that it took me some time to figure out how it worked.