So should they listen to Tom and lower their price? No, in my opinion. I say this because the company has access to a virtually unlimited supply of remnant advertising. They have likely spent the equivalent of 100 million dollars this year alone based on my TV watching research. (I think I finally found a way to expense my cable bill :-)
In addition, customers want one bill and this is a way to provide that. They also want minimal support issues and dealing with a single company is easier than dealing with more than one.
Finally, a price war is good for consumers and bad for an industry. You want to ensure VCs will run away from VoIP screaming then mention a price war. You want to make sure that top talent doesnt decide to develop products in VoIP, then mention a price war. Prices will decline over time as new entrants are pouring into the space.
In my opinion Vonage and CallVantage are crazy to engage in any cut-rate pricing because they have established themselves as premium brands. BMW and Mercedes dont get into price wars. Market share is great but profit is what separates the adults from the kids in this game.