I am personally using this app since many days, so far my experience with this is very good. This app provides very nice and seamless calling features. The video quality is very good. Mainly this app is used to talk with people staying abroad.
The video calling quality is complete dependent on your internet speed. A lot of people blame this app for the video quality, but the problem exists in their internet speed. If you at wifi or 4G, the video quality is too good.
The audio calling is very good at any speed. Even at 2G speed one can easily talk with great easy.
It also supports other messaging option like text, image and video sending etc.
This app is nice and has many good feature. It worth a try.
Thank You.