I'd prefer Skype to talk and chat since I can use it in my computer. On other hands I like the "social media" alike that wechat has, so I can see other users pictures =P
I love skype. I have never heard about wechat but I have heared about QQ.
I don't like WeChat because it doesn't work in landscape mode on Android: this missing feature makes it almost unusable for me.
I love Skype :)
Actually I prefer QQ.