good, fast, cheap. Pick 2, you can't have all 3.

You have to remember that when you use external be it the cloud or VoIP (Skype, MagicJack, Primus, etc) you are putting your business in the hands of someone else. What if you cloud provider goes down? How long are they down for? Can you run your business without that data and how much do you lose per hour down? What happens if Skype is down or not available? Maybe employees can use their cell phones to call out but what about customers calling in? You may be able to give sales a tablet but not a design engineer or programmer.

One has to do a risk analysis and decide how long can you be down and how much does it cost per hour when you are down. CIOs and management need to do this rather than jumping on the last ad on the back page of that tech magazine.