Gertrude's experience and opinion of Skype is consistent with my own. My line download speed is 5-6 Mb and I have never had better than mediocre call quality on Skype, with dropouts. I realise that this could be due to poor line quality/speed at the terminating end of the calls, but I have tested it by calling people who have equal or better downolad speeds and the quality has still not been acceptable.
Skype is cheap, and like most cheap things, not as good as good as a more expensive service. As the difference is marginal, I prefer to pay for convenience and quality.
On a related topic, I remember many years ago, as a spotty lovestruck teenager, calling a girl I'd met on a skiing holiday in the Tirol. She lived in a remote village on the west coast of Ireland. I called our local operator and asked for Ballyclondroid (or whatever it was) 14, she called Dublin, who called Limerick, who called ..... and eventually got through to Ballyclondroid, asked for number 14, and I heard the broad Irish accent coming back down the line : "You'll be wanting the O'Reilly's then, they're down at the O'Connors for lunch, I'll put you through there, it's number 18."
And on yet another note, you don't have to be a teenager to be lovestruck!