Although I'm not tasked with voice (I should be), I was instrumental in my company choosing Sonic. It was really a no-brainer as we were previously an AT&T POTS customer. Switching to Sonic's PRI has saved us thousands on our monthly phone bill with no change in quality, and I'm sure less headaches when it's time to call for support.
I'm not all sure on the #'s, but I know we have multiple incoming lines (6 to 8), about 200 extensions, and an old Avaya Merlin PBX. Next on the agenda is to have voice brought under my purview. I'm the one and only IT staff member. #spiceworks