It's my personal experience about IMO it is the best Application for easiest video calling, chatting and free calling through the Internet.I always use this Application for most of the video calling I am calling with my Family members in the foreign country. When I was talking on IMO through video calling it never hang and it gives you so good video quality I love it and also so good quality of sound.An important point is it is so private app if your phone will be Locked at that time of talking with someone then, if any person calling you on IMO And another person can see the call and taken to receive but he can't really see you with Open your phone and after only receiving the call.