WhatsApp is the best because of following reasons:
Personal
While Facebook let's you put up everything right out there, mediums like WeChat and Whatsapp are more personal.
Surat to Ahmedabad Train All your chats are private unless on a group and there's no fear of accidently posting something which can go 'public' if you forget to tweak security settings
Security
In terms of data, Whatsapp and WeChat are much safer as compared to Facebook. While it is still not advisable to share personal things over Facebook considering the privacy glitches and fears of hacks, there's no such issue over Whatsapp. Unless an over-adventurous hacker decides to hack the complete database of Whatsapp and go through each and every account, we guess your data is relatively secure as compared to Facebook.
Quick
Imagine you sent a message to someone over Facebook. Now begins the endless wait of checking whether the person received the message or not and another wait till he/she comes online to respond. Whatsapp and WeChat are instant and very quick ways of messaging. Response times are much better.
Real Friends
You might have a 1000 friends in your Facebook list. But how many of those friends do you really connect with? Mediums like Whatsapp and WeChat let you stay connected to your friends,
Cell Phone number tracking your real friends whom you know in flesh and blood