I have read a lot here and elsewhere about the virtues and caveats of Google Voice, PhonePower and Anveo. I would prefer to just use GV but I realize it is down at times so I am leaning towards PhonePower since I believe it's cheaper and more user friendly that Anveo.
I am currently using GV and it's been flawless. Would PhonePower be the better choice for reliability and configuration?
Your experience should weigh in, right? If Google Voice works well for you, just stick with it. It is, in fact, highly reliable, but not perfect. Many problems are caused by users themselves, who, for example, forget their user ID and password and complain about all the business calls they're losing, or other such human error. Occasionally, problems occur with calls to or from limited geographic areas, or between certain carriers.
Phonepower is a great alternative. Many of us also prefer Callcentric or voip.ms. You can get a very inexpensive, pay-per-minute account with one of those two, and configure it as a backup on one of your OBi's other service provider slots. Keep in mind that some sort of E911 service is essential, and by adding one of the SIP VoIP providers to your OBi, you've got that covered.
Anveo has been working great for my parents.
I setup their obi to use GV for outbound calls so Anveo is just a DID & E911 provider for their old Verizon POTS number.
Using NOMOROBO in addition to Anveo's "blacklist" feature has cut their spam calls to zero.
For $40/yr my Dad is happy.