In UK. I have a Galaxy S4 on PAYG with T-Mobile. I also have 3G mobile data available. Skype V126.96.36.19950 is installed on the S4 and I am able to make very satisfactory video calls using either low or high quality video whilst on Wi-Fi. With no Wi-Fi connection and using Mobile Data I am able to make a connection but the video aspect freezes after a couple of seconds using low or high quality video. The adverts show people using 3G and video calling with no seeming problem. Is it me or is it overzealous advertising?