I'm using Packet8 on RR cable. So far, for the first month it has been absolutely wonderful! No dropped calls, no static, echo, nothing. Just clean audio from both sides. For an additional 4.95 a month I had a virtual phone number set up for distant family. I'll never return to land lines again. I have read on other sites some problems related to Packet8, but I'm here to tell you, they don't exist on my end.
When I first received the module and hooked it up, the call quality was a little less than perfect. A quick firmware upgrade solved that issue instantly. If you have a solid isp (no packet loss, great uptime, etc.) give them a try. I don't believe you'll be disappointed.
BTW, I'm not affiliated with P8 in any shape form or fashion. I just call it as I see it.
Nice form you guys have here. Awesome speed test too. I had been putting off joining until I saw this post.