I honestly think that would differ with each person you speak to. One person may do well with one program while the next may not do worth a damn with it..... it all depends on what YOUR sites are doing and how your surfers react to what you give them. Every site/program works differently when teamed up together.
I say this because I tried this a few years back, I built two identical sites on two very different domains and I had two completely different sets of surfers..... it only made sense that if they bought from one, they would buy from the other, but this wasn't the case at all.....
I think this is seriously something you have to run the whole trial and error thing for yourself.
