AFAIK you can use it to call US & Canadian numbers from Ireland, but that's it for now, although it should be possible to call from the gizmo in ireland to a US number with another gizmo attached and recall outside the US from there.
Yes, I have it! A friend from America got it for me as a gift. It's great! Once you actually figure out how to set it up, it's very good. Be aware that you need a good quality phone to make it worth your while. I hooked an old phone (not cordless, the old 1980s/1990s) type to it and the sound quality is poor. Best to have a modern phone with very good sound quality and volume adjustement.
it's basically very good. But I have a lot of contacts and friends in America.