I use an Arca-Swiss Z1 on the Induro C414 with a Wimberley Sidekick with my 500mm, when I don't hand hold it. It's a solid, smooth combination that's easy to use. I haven't tried any of the competition extensively enough to comment on them in comparison. The little bit that I tried another, like the RRS and Kirk, I felt no real preference for one over the other. I see that Induro just introduced some good looking ball heads, but haven't seen one in the flesh.
I can assure you that an A-S Z1 will be wonderful with your Sidekick, but I suspect that there are other good alternatives.