What are pros and cons of VOIP digital phone?

I really don't see any disadvantages of VoIP, and I work in the telecommunications business. The advantages are that you can use a company like vonage and you can pay a single monthly fee (I pay 25 bucks a month plus various taxes) and I can call my parents in England all day and every day for nothing extra and my wife can call her family in California all day every day for no extra. In the old days of voip, the calls were subject to a slightlly annoying delay, but now you cannot tell a voip call from a regular telephone call.
Phil