I use Simonics' Google Voice Gateway with a GV number. It's not my main number, so I haven't done an extensive comparison of the CNAM info provided as opposed to Callcentric or anyone else. It seems to me to be roughly equivalent.
In terms of uptime, it's been as reliable, for me, as other service providers. The proprietor of the service, Bill Simon, has an excellent reputation in the VoIP community.
Setting up Simonics is as easy as setting up any other Generic Service Provider via OBiTalk. Needed information to do is provided once you sign up. It's a $6 one-time payment, which is refundable should the service not work out for you. I see no risk in giving it a try.