the two I have used to date must route their calls via Skype or the internet in some way, but its like talking through water
Frank I have never had an issue with Skype and I use it all the time to call landlines in the UK from Poland.
Only this morning I was speaking to my mother and the only reason she couldn't understand me was that I had a mouth full of cornflakes, and then the reply came, "don't speak with your mouth full", she still can get me over a thousand miles away lol
I guess there are issues with your internet speed, but I have 1Mb and have no problems :O)