I've only used Callcentric, Voip.ms and Anveo from the Obihai list.
Anveo doesn't have local POPs but it has automatic failover, so if the main POP dies, you automatically get routed to a backup, no intervention needed. I also like the callflow because I have it set to do things like DISA, fax etc. It isn't that cheap though depending on the features you need. It isn't nearly as user friendly as Voip.ms which sucks but potentially lets you do a lot more interesting things.
Callcentric is more expensive but it has local access numbers across the world for cheap calling, I used that feature in Europe and it was really nice. They also have unlimited calling $20 plans and rock solid stability but are among the more expensive providers. They operate much more like a phone company.