I know a ton of people who set up a G+ profile and I found both the web version and mobile app to be superior to Facebook's offering. Plus they had better image hosting and they had good text/video chat before FB updated theirs.
But in the end it comes down to critical mass of users (and particularly, non-early-adopters) on Facebook. You might get your other peers to try out a new service if you're into trying out new sites/services but unless you get everyone to make (and use) a profile the way most people seem to at least have a Facebook account, you're stuck maintaining two profiles on two sites and switching between them depending on who you want to share that update or photo or link with.
In the end it didn't matter if they had a modestly better site or mobile app because nobody wanted to post to two sites. And since, unlike email, these things don't operate on any sort of standard protocol, you can't just switch your client and let grandma keep using her old one so it fizzled as a FB competitor.
(I still use it for several niche interest groups though. Also I think circles are vastly superior to whatever Facebook has for granular control of who you share something with.)