Voice over Internet Protocol (VOIP) is definitely here to stay. If you haven't checked into it yet for your company, you should. It could possibly save you a ton of money. The quality is generally excellent now, and this is not your old voip in the beginning where the call quality was marginal at best. This is now a very mature product, and in fact, the long distance companies have been doing it behind the scenes for a long time. If you ever made a long distance phone call, odds are some part of the call was run over voip, with or without your knowledge.
However, when choosing a voip provider, you need to be aware of one very important point. 911 calls are handled differently between the providers. Very differently. With some providers, it doesnt' work at all.
Unfortunately, some VOIP services aren't tied in to the 911 system and this can quickly move them to the bottom of your list of potential companies to work with. Then again, on the opposite end of the spectrum, some VOIP carriers offer Enhanced 911 service, where 911 calls using your VOIP service automatically send your name, location and other info. These companies might quickly find themselves at the top of your list.
The bottom line is you should investigate this exciting technology, but make sure you ask about their 911 capabilities during the discovery phase. My recommendation? NGT (New Global Telecom) at www.ngt.com I use them in my business, and they are first rate!
To Your Success,
Tim