Sure there will be some cross-over but for the most part you'd hope to be reaching new clients - right?
I don't know. I find the photographers that I follow, use it primarily to follow other photographers and share our work. If and when I'm ready to launch the business side, then I will use the studio name and not my individual. Many of the Google+ people are not big fans of Facebook. Kind of "PC v.s. Mac" like.
I suppose when that day comes, it can only help having personal followers established to then pick up on the business side. I'll have to check out Google business.
Doug