It doesn't really matter if Google+ is better than Facebook, in terms of features or looks or anything. People won't switch just because it gives them a better way to do something they already do. People will switch if a) Facebook becomes annoying for them (low availability / bad UI changes / whatever) and b) if Google+ gives them something new to do.
I use both (and twitter too) because the two have different audiences and different dynamics - basically, I use Google+ as a Facebook for Twitter-folk, while I use Facebook for people I know from real-life. But it's all blurring.