I like whatsapp but don't like the idea of it charging. Luckily I was one of the first to download so have lifetime membership woooo Who else agrees though?
I have recently started using WhatsApp. I was kind of hesitate to try WhatsApp because I thought WhatsApp were some kind of IM messaging system like all of services into one (Facebook, Yahoo, AIM, ICQ, etc etc) but I was sure wrong after I found out that it was different than I thought and I gave it a try and immediately like it then got my mother to download app and install it on her Iphone as well, even though we both have text messaging service for our Iphone 5S I like WhatsApp a lot more because it has more features, like a blog post I made on my website I call WhatsApp "Text Messaging on Steroid" haha.
Whatsapp. I'm interested in what will happen to it now that FB has bought it, but so far that's the next best thing to use after iMessage.
Still now I am happy with Skype and Google Hangout. No intention to use WhatsApp/Viber/WeChat/Line in near future.