I have been using Whatsapp for the past 6 years and Iam really satisfied with its interface and user friendliness. It doesnt complicates things much and all that we should have is the mobile number.
Works well even with 2G data. And also the calling feature is excellent. Both the video and audio calls are of great qaulity. Also recently there can features like we can change the font is also helpfull if we want to stress on a specific word. Also now we can tag a message and reply for that specific message has helped me lot to avoid confusions.
Message recalling option is wonderful thing. It had helped me a lot as Iam someone who sents wrong text usually and its very unpleasant to tell sorry everytime.
Status feature also is a wonderful as we can share the things we went through with others. The status could have some additional features like adding of time location and all like instagram.
Iam really satisfied with this application.