We have been using Viop for our business now for apporx 14 months our provider is Go Talk Australia. The thing i dont understand is "why everyone is not on VOIP" our business phone bill has gone from around $500.00 per month to ----wait for it $25.00 per month and a large number of our calls are MOBILE !!!!
Call quality is great, customer service is mmmmm avarage which is the only down side to go talk, but when you add up the savings i guess you can put up with a wee bit of average customer service. Customer service could be improved by NOT GOING OVERSEAS for the call center and baseing it here or at least have people whom can understand what you are talking about.
But other than that they are great and will stir up the big boys
http://www.gotalk.com.au/Products/BusinessSolutions/BusinessVoIP/tabid/569/Default.aspxSo check this link out for all the great deals from Go Talk
Cheers
David