Hello!
Viber is worst Internet messaging Application because you cannot take a backup of your messages which is most important. You cannot import that contact list and save it.
#1. Concept: All messaging Apps were designed by following the Microsoft’s Skype App and many application failed because they didn’t understand that in real world limit kills because when you create something revolutionary you do not know in how many spheres your creation could fit in. Viber allows 7000 character limit which is certainly less when you compare it with it’s peers. Concept of sharing a message should not be broken with such limitations. You still cannot send many file format as attachments this’s another minus point that beat the concept and create an urge to find some application that does support something that could meet all user needs.
#2. Layout and Design: Layout is good but sticker emoticons are very big and are good to have but they could really do other things to improve their app rather then this. Design is very nice and it is appealing if you consider it look wise. Architecture wise it is again something that now a days developer are doing ditching the 32 bit processor and user and forcing them to adopt 64 bits processor. Designer never thought about that people might need to have a backup of their messages. There is no such provision. It’s a bad design then as backup is very basic thing.
#3. Feature/Functions: They have big flashy stickers and you can buy some more I do not know who really does that because unless the person that you will be sending that sticker too has also not bought those stickers won’ be able to see your sticker emoticons. So this means that they are just fools while creating this feature. Function it does not have much to offer as you cannot send big files too and it foes not supports many formats also.
#4. Usefulness: It’s not standing out as a something you must have you can easily convince your friends to use something and tell their contact to try other good messaging app that are more useful than this. It is not useful as you cannot import your viber contacts also, blocking unwanted people is very cumbersome and all people will get an alert when you join viber and you do not always want that everyone knows what you are up to.
I strongly advice you to try other messaging App that has tons of function and have encryption and are open software and are not selling anything and you can send massive files. This means you can share all format even movies, songs with your friend and create very very large groups. Viber is a very basic App.