Google plus might not be the place where you are spending majority of your free time. The facebook has the statistics in its favor in terms of time spent. But still Google plus is a silent winner in the social media arena.
Google plus engagement is specific
Google plus provides a great platform for engaging with people who are genuinely interested in your product. On the other hand, Facebook is a ocean where you can even fish likes (buy). The more engagement does not necessarily reflect the actual scenario. But Google plus, with its no advertisement model is proving to be a great platform for online service providers. The deep integration of Google plus into the search engine is also helping the cause.
The search always ends in Google !!!
Facebook provides a great platform for brand engagement and awareness. But the consumers usually redirect to search engines like Google to check out for detailed reviews and price comparisons. Until the Facebook comes up with a very innovative idea to offer a more complete experience(graph search is not enough), the game is always in favor of Google.