Ooma works as well as everyone says, and it's ultra-simple to get up and running.
The biggest PITA is how they handle international calling. Unlike "normal" phone companies, you can't just pick up the phone, make an international call and have the charge show up on your monthly bill. Like the cell companies, they really want to sell you a recurring monthly bundle of international minutes -- which you may or may not use. If you make some but not enough international calls to justify a monthly bundle, then you have to pre-deposit cash into your Ooma account that, like Skype, you draw down as you call -- at much higher per-minute rates. And unless you upgrade to Ooma Premier service for another $10 / month, calls to Canada are treated the same as other international calls. Be warned.