I use provider CNAM for all my trunks (primarily Flowroute and VoIP.ms) other than Google Voice, but my volume is low enough that it doesn’t make an appreciable difference in costs–a fraction of a cent per call for good data.
I do use TrueCNAM for spam scoring and have found it pretty accurate. However, I would not rely on them for actual name information, as their coverage is still very small and reliant on contributions to their DB. Even though they claim to have a large number of providers who do contribute to their DB, several test numbers I ran through them failed to give any information.
I’ve just switched my Google Voice trunk over to pull CNAM data from OpenCNAM instead of the trunk because Google doesn’t do CNAM lookups. Waiting for my first inbound call to see how it works. Tests on opencnam.com passed with flying colors when I threw several test numbers at it, including some that I know have never touched VoIP (and so couldn’t have been contributed by VoIP providers), like an AT&T cell phone, landlines from ILECs and CLECs in several towns, plus of course VoIP provider numbers, etc., and all were looked up successfully and accurately.
I can’t tell from Google whether OpenCNAM actually does real LIDB lookups or not (they don’t advertise doing so, and older discussions on VoIP forums seemed to indicate they didn’t as of 5ish years ago), but if they don’t, then they have somehow managed to assemble an extremely comprehensive database that’s on par with the LIDB.
(FWIW, I have IncrediblePBX.)
