Video calls are more susceptible to data delay and loss than a pure voice call. This is due to the increased amount of bandwidth required to carry the video channel in addition to the voice. So, your overall performance on video call is going to depend much more on the bandwidth capabilities at both ends of the call than normal. Generally speaking for most social users, the video call performance is good and acceptable to most.
It is because of this general bandwidth concern that our video calling is no better or worse than Skype since they face the same bandwidth issues as our services do.