Use 1SC for one project, moving all else to Nanacast.

Can't really run down the features/benefits of why other than to say Nanacast is really an all-in-one with awesome technology behind it. I see it overtaking 1SC unless they do some serious catching up.

InfusionSoft is also popular though I've never touched it as admin (I've only seen it from the affiliate's point of view).

And I also use RAP for the lower ticket, buyer-list buliding projects.