I have been a Sonetel customer for over 2 years. In brief, when it works (maybe 50% of the time) it's OK (not good, just OK - often the call quality is extremely poor and delayed).
However, when it doesn't work, despite polite emails from customer service, days and days go by before the matter is fixed meaning that if you rely on it for business, as I do, you are pretty much screwed. In my current situation, it's been an entire work week and it seems like they have just forgotten about my file.
I am currently looking for another provider because I cannot handle the unreliability. I thought Skype was bad, but Sonetel is sadly worse.
Product or Service Mentioned: Sonetel Phone Service.
Reason of review: Bad quality.