I have been using AT&T callVantage for the past 12 months with no problems. 99% of the time the distance end does not know I am using VoIP, they all think I am right next door because the calls are so clear. The calling plans are not bad, I have the unlimited local and LD plane 29.95/Month. https://www.usa.att.com/callvantage/index.jsp?soac=64528