I have terrible quality with GV (2 different numbers), and I don't think it's the router. I have only 150kbps upload so I know it's tight and wish I could force G.729, but it seems like it will always use G.711u. I read in other threads that you recommend port forwarding but I believe that there are security risks with that. Can anyone confirm please. The call quality is totally unusable, it's extremely choppy and distorted. I would appreciate any ideas. Thanks.
Choppy and distorted call quality is probably not a router issue, but it might save you a lot of time and grief to verify that by temporarily connecting the OBi directly to the modem just to rule it out. Reboot both devices after making the direct connection. If the problem doesn't do away, at least you know it's not the router.
Choppy and distorted call quality is more likely to be the result of insufficient bandwidth, packet loss, or high latency and jitter (inconsistent latency). Do a continuous ping of Google voice for a while to check for latency and packet loss:
C:\>ping /t 74.125.157.125