The problem with gTLDs is that there is no ceiling on the registration/renewal price for those domains. If a given gTLD takes off because, for example, someone writes a blog post about how great it is to just use it for your family's email addresses (great idea, by the way), the owners of the gTLD could quadruple the renewal price next year. Of course, some people spend tens, hundreds, or even thousands a year on domains anyway, so I suppose this only applies if you're particularly price conscious.
Interesting point. Honestly, hadn't thought about that.
Given I'm all in on my .family address, and demand might drive up the price... I would like to revise my comments to say WHATEVER YOU DO, DO NOT BUY A .family ADDRESS!!!