I have been using OOMA for over 2 years now. Recently I am having trouble with their service while using calling card to make international calls. It looks like they are blocking the use of calling cards from OOMA in order to force customers to use their pwn international calling packages. Chatting with and talking to the OOMA support has not helped. All they do it to ask us to reboot the device and try again. Their technical support is either incompetent or they are intentionally not addressing the problem.
I have been using the OOMA core since 1/1/2010. I have the Premier plan, which only costs $10 a month. It is cheaper than what I had w/ Frontier for $32 a month (no features).