I've used Pure-Voice VOIP services for over 2 years as a host for my Ventrilo service for an online gaming community.
My group actually has the resources to host a TeamSpeak Server but we went with Pure-Voice initially because the hosting service and its servers were more reliable.
It seems that over the last year, their billing department has deteriorated significantly. I've had 2 different instances where no invoice was issued to my account, no email reminder about payment was sent to the email address on file and even their online tools didn't show a past due payment. Within 2 days of the payment being past due, my service was shut off without warning. Their customer support via the phone is non-existant, even with a phone number provided, it goes to voice mail every time. I have to submit a ticket and wait for a response via their ticket system.
To their credit, they did resolve the issue within 24 hours but that is 24 hours, without warning and without service that 50 people rely on to communicate (during peek hours from 2pm-10pm PT).
In addition to the above issues with invoicing I also experienced an issue where my payment schedule was automatically changed from Monthly to Yearly without my knowledge. They tried to charge my account $240 for a year when my monthly payment was $20 and the account I was using for this service DIDNT HAVE $240 in it. This caused not only our service to be shut down, but an overdraft charge to the account. Again, this took another 24 hours to resolve and I didn't end up getting money back for the overdraft charges but did get my service restored.. in addition to a one month credit.
Anyway... we are planning on switching over to a TeamSpeak and have recently been using Skype as a means of communication instead. I've got to say that even if the voice codex is a bit more funky, the service and the fact that I'm paying nothing for TS is MUCH easier to deal with.