Google + does matter but it's weight is not as effective compare to other SEO strategies or technique.
Do you think that G+ will really rival FB in usership? If so when do you think that they will be on equal ground?
You should use ripples more on Google Plus to gauge how people are responding to your links. otherwise, Facebook is better as per my opinion.
As we are concentrating more on google searching you drive maximum and effective traffic from google +
Since, traffic depends on the visitor and facebook have more active member then Google+, so facebook is the better source for getting traffic.