What are the disadvantages of a PC-to-phone VoIP?

What are the disadvantages of a PC-to-phone VoIP?

Jim Gurol (VP of Operations, Tierzero) gives expert video advice on: What is PC-to-phone VoIP?; What is the 'softphone' used in PC-to-phone VoIP?; Who can I call using PC-to-phone VoIP? and more...

You might not want to use a PC-to-phone to make outbound calls if your call quality is not as good as your landline. The other reason is you will pay a monthly fee for that service, so if you already have an existing phone service you're going to have to pay that on top of whatever you have, so those might be some of the reasons you do not want to use a PC-to-phone to make your calls.