Currently there are over 2.4 million subscribers so it is logical to think that it works pretty well. From what I have seen up to this point that is indeed true. VoIP has come a long way in the last several years with call quality improving greatly. Of course, with any company that has over 2 million customers you are bound to have those that complain. When issues do arise it is generally a result of a slow or faulty internet connection. A poorly running computer can also cause problems with the service
In most cases the problem is not with the service itself, but if you do have issues most problems can be solved in-house by calling the Vonage support phone number. From all of the info I have gathered I have determined that for most customers it works extremely well and I highly recommend it as an alternative to a traditional land line. It's definitely not the cheapest VoIP service out there either but remember that you get what you pay for. With them you pay a bit of premium which guarantees you good call quality and great customer support for billing related issues and awesome technical support for technical issues.