It is safe to say that Whatsapp is the biggest revolution in Instant Messaging, It is clearly the leader among Cross Platform Instant Messaging apps. However one thing that Whatsapp lacks is support for using it on Tablets, since the WiFi versions do not have an SIM card slot. Also, most 3G capable Tablets do not allow the traditional SMS and Calling features.
Setting us Whatsapp on a Tablet is very easy. Whatsapp requires a phone number to register your device to. The only drawback of using Whatsapp on your Tablet is that if you cannot register more than one Device to a single SIM. Hence if you wish to use Whatsapp on both Cellphone and Tablet you will have to buy a dummy SIM card.