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i use VONAGE voip and the service is great. is cheap compared to AT&T, SPRINT and other phone service providers. There are some drawbacks however, If nyou loose a internet connection for some reason, you can not make or receive calls using your voip. And believe me , you can loose your internet service, at least with COMCAST. When I first started my Vonage, it seems that my comcast ISP would go down at least twice a month, usually in the early , dark, am hours, when comcast thought that people would not notice it. This was about a year and a half ago; but now , I do not notice any interuptions in my comcast service at all. But, if the above should occur, Vonage has fail-safes to ensure that you do not miss any calls. They have a web-interface that allows you to set a number that your calls are forwarded to in the event that this does happen. They call this "NETWORK AVAILABILTY" . With this feature you can have any incoming calls forwarded to you cell phone if you ISP goes down or Vonage goes down. But, in my 4 plus years of using Vonage, Vonage has never failed me once, It has always been Comcast. So, Yeah,especially if this is a Start-up business, and there is nit alot of extra money, then, I can say from experience that atleast Vonage would be a good choice for a VOIP service provider ***I am not affliate with VONAGE, its agents or services in any way, shape or form. I AM A CUSTOMER. Becarefful when you search for Vonage on-line; if you mispell the name by one letter, you will be redirected to a website that offers VOIP service that really is not VONAGE