Re: Google Voice
Google Voice has been out for years. I've been using it since Google bought GrandCentral. I believe, I've been using it for more than 5 years already.
Nowadays, I use Hangouts Dialer to make phone calls (US calls only). Whatsapp for intenational calls (not bad really), and of course, Voice and Whatsapp for chat and txt.
What I like to see is a comparison between Line vs. WeChat. My family and friends are stuck in Skype, but I'd like to give'em both a try. I like the Shake function. Sounds fun.