I recently decided to see if I could "cut the cord" on my home wireline and go with MagicJack. It had received pretty good reviews, been around for a while and, for the price, looked like something I should check out.
Sadly, I was very disappointed. The call quality was good, when it was there. But when it wasn't, it was a bad as a bad cellular connection. And then, after one or two successful calls, it would start acting up. I'd pick up the phone, dial a number and after the first three digits, I'd get another dial tone. Once this occurred, I would be unable to make any calls until I rebooted the PC. Nothing in their FAQ or troubleshooting literature addressed this and I just gave up on it, put the USB device away and cancelled the service.
I'll have to give this one a big thumbs down.