I did a bit of research on this a while back when I changed from handmade cords to chains, since pendants on chains sell WAY better than cords :(
Anyway,ball chains usually make people think of dog tags, which if you expensive silver stuff like me, doesn't work well.
Both link chains and rolo chains are good choices, it really just depends on what look you want to go with for your brand. I actually ended up with rolo chains myself, though my first choice would have been box chains, as they great for unissex designs, but they are by no means cheap so i went with my next choice, the rolo chains, and I must says I have grown to love them and have even gotten feedback on them...