We’re a small credit union with 5 branches in western WA supporting about 70 users. Two years ago, we decided to purchase a new VoIP phone system and, in doing so, to switch from PRI to SIP trunking since there were some cost savings to be had in doing so. While this proved to be one of the more complicated parts of our conversion to the new phone system, we have not had any trouble with SIP. We were lucky enough to have a phone vendor well versed in this conversion, and they were able to assist us in making sure that everything was in place as it should be for the new system. In looking back, I don't believe I've had a single instance where I needed to call CenturyLink for a problem with our SIP trunks. We are happy with them as SIP provider and not looking to change any time soon.