I Have Packet8
I got Packet8 to check it out.
www.packet8.net . The sound is better than I expected. Usually no different than POTS (plain old telephone service). Sometimes, there's an interruption in the background noise between spoken words.
Now and again, a call will get interrupted, sometimes only one side. I'll keep hearing, "hello! hello!" so obviously they stopped hearing me while I hear them just fine. I'll disconnect, press Redial on my phone and it will be fine again.
They sent me a box that I plug into my wireless router at home, then I plug a regular phone and a cordless phone base into it. I take the box to work most days and plug it into an Ethernet outlet and plug a spare work phone into it. Wherever I take that box and plug it into broadband service, the phone will ring when somebody dials my number, and I can call anywhere in the U.S. and Canada for the flat $19.95 fee. Goodies that phone companies charge for are included: caller-ID, call waiting, 3-way calling and call forwarding, for example.
Although this box doesn't require a computer for phone calls, you may need to plug one into it to change its default settings regarding IP addressing to make it work with your Internet source.
The packet-switched Internet is designed with not-reliable connectivity, so VOIP likely will never be as stable as the circuit-switched phone system. Still, it works great most of the time. If you have reliable cellular service to fall back on, you could be okay with VOIP. Don't depend on it for non-casual business, though.