WeChat is a free
WeChat is cross platform and includes individual and group messaging with text, voice notes, images, videos and location data. WeChat allows free HD video calls, secure message storage and does not invade your chats with intrusive advertising. WeChat also supports video recordings, syncing of phone contacts and GPS.
The interface of WeChat will be familiar to anyone that's ever used WhatsApp. Chats, Contacts, Social and Settings are listed along the bottom and new notifications appear in your WeChat timeline. WeChat also features an interesting real time Live Chat feature for groups and you can invite people into the chat using QR codes. WeChat also saves your chat history so that you can search it any time.
Other than that however, WeChat is just another WhatsApp alternative that doesn't offer anything new. As the developer is based in China, it's also considerably more popular in Asia than the rest of the World.
WeChat is an interesting WhatsApp style chat client that can be a bit overwhelming with notifications but is an interesting alternative to WhatsApp.