Primus
I have used Primus for about a month now, and overall I am pleased but there have been issues that need to be considered.
Firstly, the voice qualilty for me is about the same as cellular. It is not the same as a Bell land line. This may be due to any number of issues that are only relevant to my physical location and the Rogers cable internet service I have. I have also had technical issues with strange ringing, and inability to make an outbound call. Shortlived and fixed with a phone call to their tech support.
If you live in an older house, as I do, with creative wiring for the jacks, it may take some sorting out to disconnect from Bell physically and get al the jacks in the house working.
Overall, I like it and wouldn't go back but I had some growing pains.