there is a bug that might be treated as limitation, but it's still not documented at all. there is no information on RV260 datasheet page(https://www.cisco.com/c/en/us/products/collateral/routers/rv260-vpn-router/datasheet-c78-741409.html) as well as into Admin Guide.
in short words, whoever need PPTP on WAN and QoS it's pretty much like RV160/260 is not your choice. it might be the same story with all RV router at all, but have no a chance to test as own only RV260 and Cisco is not providing any details unless you buy it and rise support ticket.
not really sure if it's reasonable to wait any changes on datasheet webpage as the bug is terminated.
