Good "Free, good quality, and good support"
Overall "It's an awesome deal"
There is not much to say when they give you a DID and unlimited calling for free. I dumped the POTS and bought my own ATA for $30 and paid $50 for the configuration file. I find the $50 config file more than reasonable considering I get a DID, unlimited calling, voice mail and caller id for $0 a month.
Their support is great, the forum is very useful, very easy to get in touch with and they are always there to help.
With the ATA, the voice quality is perfect. Didn't have a problem after constantly trying different numbers to stress-test it for a week. In fact, it's better than my cellphone and as good as a post line.
I read before that some people had trouble getting the config file or had to wait up to a week, but when I called, they activated it on my online account right away and I had access to the password before the call to purchase the file even ended.
All in all, zero problems, 0 monthly fees and a perfectly working line makes me more than happy!
Edit after several months:
Aside from a few small bugs that they're trying to iron out after a server upgrade (VM indicator won't turn off on my phone, for example), it's still working great, line quality never had any trouble and the price is still $0