I installed ours yesterday and have no problems thus far. It's installed on my wife's desktop PC for convenience since we move the laptops around far more frequently. I had it installed on my laptop running Windows 7 Ultimate, initially then uninstalled and installed it on her desktop running Windows XP Professional. Both installs worked flawlessly as did the uninstall.
To uninstall you must download and run mjRemover.exe from here
http://upgrades.talk4free.com/tools/mjRemover.exe for Windows or for Mac download and run
http://upgrades.magicjack.com/tools/...teUninstall.sh.
Both of us have cell phones from different providers (T-mobile and Verizon), so if the ISP (TWC) is down we can still communicate.
So we're still noobs with it and opinion is subject to change.
FWIW, I got one because one of my close friends; who left GSA to work for DOD, took his to Kuwait with him and I've had 3-4 phone conversations with him and experienced no problems. Lastly, I will NOT miss the monthly bill from AT&T...