I use Skype and find it adequate for most purposes, although the quality of the line is variable. It has been suggested that 'Wechat' has advantages in enabling voice recording to be made, which can be replayed. I normally do not use the camera with Skype, but I was unaware that it had an impact on the quality of sound.

Although Skype is not perfect, it does the job :) I use it everyday and it sometimes happens that I need to turn off the camera to have a better connection.