IPv6 support is basic at best. The zone-based firewall is very prescriptive and limited. ACL stuff is not great. To increase the MTU of the physical interface connected to the ISP I would need to hack a systemd unit that did it on boot (I either need it at 1508 so the PPPoE interface uses 1500, or I need to MSS clamp it and have it effectively reduced to 1492). Initial configuration requires the device to be connected to the Internet.
There were a few other niggles, and in the end I just found it easier to do what I need on OpenWRT.
There were a few other niggles, and in the end I just found it easier to do what I need on OpenWRT.