i use gizmo for calls out exclusively. gizmo is invaluable for my international calls, the cost at what would be otherwise peak times is truly minimal, and i am saving bucks.

there are sound quality issues: internationally, the small delay makes conversation awkward (remember those days?). within california i am having some issues with roughly broken sound: even the dialling sound itself is compromised. but 80% of the time, there is no such problem, and the sound is excellent.