Since taking QTTalk's service, the only thing they have done efficiently is billing my credit card. It took weeks to get the service working originally with any reliability. Not all features work to this day, some 8 months later. Their directions for use of special features were non existent.
I purcahsed their Domestin Unlimited Plan only to learn they do not mean Umlimited, they really mean 1500 minutes. While that normally does not pose any issues, I believe their description and advertisement are misleading.
Their voice quality is marginal, useable but frequent crackles and noises. Their system has frequent outages, usually only for a few minutes, but I have no confidence in their service. It it were not for my cell phone, I would be without phone service frequently.