The Facebook Messenger is a must download app for most people who use Facebook - it's just a very convenient way to keep in touch with friends.
However if you want a change from the dreary looking Messenger app, Bubble Chat is a great alternative.
Bubble Chat was designed by Jackie Tran, a fantastic designer who is well respected in the design community for his amazing attention to detail.
The first thing you notice about Bubble Chat is how beautiful it is. It has a minimal design but uses gorgeous gradients and makes very good use of profile pictures. The animations used are sublime and are silky smooth. If you don't like the default colour, you can customise it and choose from a number of colours available. There are additional customization options too but they require an in-app-purchase, but you don't actually need to pay anything to use the app.