Well Skype works well on a good connection but seems to go silent for one side or the other, when conditions are less than ideal.
Skype has one major disadvantage when you work behind a firewall / proxy server, IT DOES NOT WORK !Unless you can modify the firewall to let other traffic over port 80 then http. Sometimes this will be a pain in the b*tt. Because this is where a firewall is meant for. I really hope that they will use another port then 80.I am affraid that it will be rejected by a lot of users this way.
Sorry, have to disagree with Rody. I have Skype. It works fine through a firewall -- and my firewall is *very* securly locked down. It even accepts calls (obviously using a proxy/3rdparty host somewhere. see http://www.skype.com/products/explained.html for a good techie explanation of skype's P2P implementation).Skype rocks. I made an international Skype-2-Skype call from my broadband connected PC to a 56k modem PC and it was crystal clear with very low latency.I can recommend it to everyone!