Great for VOIP.
This router has all the features you need to support VOIP on your network, including QOS based upon DSCP Tags, Option 66 on the DHCP Server, and Port Forwarding. And at $129.99, it's a great value.
What it lacks is QOS based upon source or destination IP address and more than two VPN tunnels, but I don't need the former, and can use OpenVPN for the latter. The backup Wifi as WAN is a nice feature as well.
I have had two problems with this router, but Pepwave and 5GStore have both been very responsive. The first problem caused the router to freeze up once every seven days, requiring a power cycle to restore functionality. Pepwave investigated and advised me to disable Wifi as Wan (which I had configured for use as a backup) and the freeze-ups have now stopped. The other problem related to VOIP usage, and was resolved by forwarding ports (which I don't have to do with other routers and I hate doing when not necessary).
However, Pepwave has been responsive on both of them, and so I expect that they'll be solved in firmware updates.