We have had so many problems since switching to Vonage, the worst of which is frequent system-wide outages. We aren't the only ones suffering, too, so we know it is not isolated to our server or network. Sometimes, it is regional (just in the DELMARVA area), sometimes it is more widespread. We know we are not suffering alone, but when a good portion of your business is based around a call center, we need a phone system that is reliable and connected. Vonage is neither. External calls are often choppy, and calls are very frequently dropped mid-conversation. Repeated attempts at troubleshooting have been fruitless, and incredible excuses, such as, "We need to be on the phone with you when this happens," are deflecting and pointless. If I had to decide on a phone system again, it would not be Vonage.
Please consider all of your options available. If your business absolutely relies on having working phone lines throughout the day, especially in regards to emergency services, you might want to consider another alternative.
Our aim was to provide a VoIP solution for our call center and entire office, though having a system that frequently crashes causes more problems than it resolves. It further damages our reputation as an IT leader, which has downstream impact on our bottom line.