My partner and I have two homes, one in Maryland, and one in Virginia. Instead of the Verizon Quantum routers, both locations have ASUS RT-AC66U routers with VPN enabled. Virginia is the server, Maryland is the client.
There is no problem with the Virginia site -- testing with speedtest shows about 600 Mbps throughput. [In fairness, my VPN is currently down now, and I should retest this with the VPN in operation.]
When I use the Quantum Router in Maryland, my speeds are similar, but since the Quantum Router cannot act as a VPN client, well, that's an issue.
When I use the ASUS router in Maryand, the VPN is up, but my speed drops precipitously -- 25 mpbs, which defeats the purpose on a 1Gbps connection.