VoIP deployment suffers mostly from folks trying to run concurrent legacy voice and VoIP in their legacy PBX systems.
Some hurdles for VoIP deployment have not been the tranport technology, but the fact that VoIP ystems did nothing different that the system thay already had installed. No new features, no better service and you have to: A Pay Extra to support IP, B Toss out the 2 year old legacy system and replace it with a new system with fewer features, C Figure out who supports this IT to TeleCom?
This is where the new breed of VoIP systems come in. VoIP will have significant growth from the small and medium businesses. These folks are using Centrex systems with few features or have small PBX systems that are difficult for office managers to maintain and manage. This is where the VoIP and customer provisioning features really help folks. Simple web interfaces for provisioning (add, changes, deletions)for their allocated extensions and DID numbers. Broser based portals will call loga and click to dial. Full featured server driven phones pushing content to 2, 4 and 25 line displays.
There are a couple good models out these. One (GoBeam) uses the cell phone model. Buy a bunch of line/minutes per month. Another is buy the IP phone, pay x per month per line and that is all you need.
Enterprise systems range from $350K to 3 or 4 million smackeroos. The Cisco AAVID system comes in at the low cost end. There have been articles in the last 5 months of Network Computing with VoIP deployments.
Which is better, monthly service charge managed by the service provider or a exterprise system with large upfront costs and a staff to manage it. Depends on who you are I guess. I know with service provider offerings, companies with offices spread all over the place can take advantage of service provider on-net calling and lower their costs.