Andy at VOIP Watch runs through a call test using quite a few players through soft and hard phone… Callvantage gets the confirmed flag with the best call clarity, followed by Vonage Voice Pulse and SkypeOut. I thought it was pretty interesting from his conversation, that Skype to Skype had a better sound quality to it than a SkypeOut call which used at least one landline, though he did not mention on which of the many VOIP services he received the call. I have a feeling it was Callvantage, and would bet there was no standard / traditional phone involved.