Virtual or hosted telephone systems market themselves as a better alternative to traditional PBX systems located on the customer premises. They tout advantages such as protection against obsolescence, software upgrades, connecting remote locations, and included maintenance and phone services.
But I would not count out the traditional PBX systems just yet. If you have a home office or require less than 5 or 10 telephone sets or have employees in different locations, then hosted may be the way to go. For a flat monthly fee per phone you can have all the features of a traditional PBX with none of the headaches.
However, as the number of telephone sets increases, the cost/benefit decision changes. Remember, with a hosted system, in effect you are renting, not buying. Traditional PBX systems, as function of the cost per telephone set, have continued to drop in price. The cost of ownership five years out clearly favor purchase or lease of equipment over renting.
In the 10 to 30 phone range customers should look at the ROI of purchase versus hosted. Over 30 phones, most businesses would benefit from owning rather than renting. Just because new technology is available does not mean that it is right for every business.
Also, most new PBXs can support VoIP telephones at remote locations. If a business has a main office and multiple small remote locations, they can be better served by stand alone VoIP phones at those remote locations.
The Internet has influenced all areas of personal and business life and it will continue to do so in the future. Just make sure that the technology is used wisely for your application.