I am in Alberta, Canada.
I have been using the following VoIP providers with good results:
InPhonex
They have been my primary VoIP provider for the past year. Overall the VoIP phone service has been good and reliable. Their prices are a little on the high side. I only use them because they are only one of a few companies that offer e911 service in Canada.
However, I am not impressed with the technical support staff.
They are not a Canadian company - they are based in Miami, Florida.
CallCentric
I used them as my seconday VoIP provider. I have had good VoIP service with them. Their rates are good, but not the cheapest. They are a USA based company. I like the fact that they have Calling Card access features. Their customer service is generally good.
I especially like their web account Control Panel. It is very well organized.
They were my secondary provider only because they do not offer e911 service in Canada.
Thus, I recently dropped their DID service in exchange for Voip.ms.
Voip.ms
I have recently dropped CallCentric in exchange for Voip.ms as my secondary DID VoIP phone service. Two primary reasons for this choice:
1. They are in the process of implementing and activating e911 service in Canada.
2. Their DID origination rates are very competitive.
3. Their termination outgoing rates are among the cheapest in Canada, and USA that I have found.
4. Voip call quality is generally very good (especially considering the low call rates)
5. So far, their customer service and technical staff seem very good.
6. They have multiple points of presence. They are a USA company, but also have office servers in Canada.
I like the fact that I can register with their Canada servers and have less latency than if using the USA servers.
I am currently in the process of waiting for them to implement my e911 service in Alberta, Canada.
If this transition goes well and they continue to provide good service, I will likely stop using InPhonex as my primary VoIP DID service and give that spot to Voip.ms.
Les.net
I periodically use Les.net as a backup service provider. They are a Canadian company. I have had good results when testing their service. Their termination rates are very good in North America. Their DID's and origination rates are competative. They are a growing and innovative company.
The only reason they have not become my primary, or secondary provider is because they have not yet implemented e911 services. But, they say they are working on it.
If I switch to Voip.ms as my primary DID origination service, I may likely implement Les.net as my secondary provider. It will be a toss-up between les.net and callcentric. Which ever company implements e911 first will likely win that spot for me...