I think both are good but google + is not in trend so i prefer facebook , i know google+ have some amazing features but though everyone enjoying facebook.
what is the difference between google+ and google+1 ? google+ is not used much as +1. I think so. what is your opinion friends?
If you asked me this 2 or 3 years ago I would certainly say FB. But now I will go for G+. It has good prospect indeed.
currently, i think facebook is the best because it is the most utilized and has the most potential for growth for musicians like myself. it's multi-faceted and tons of websites now let you log into their systems using your facebook account.
I use Google plus, Facebook, and Twitter all are best and good way for SEO but I mostly suggest to Facebook because it is most easy and valuable to generate high trafic.