-. clean and nice design
-. easy to use
-. FAQ in more than 50 languages
some Frequently Asked Questions :
How do I add WhatsApp to my lock screen?
How do I move WhatsApp to the SD card?
How do I backup, restore or transfer my WhatsApp data?
Why can't I connect to WhatsApp?
How can I fix problems with downloading or sending media files on WhatsApp?