Hello!,
I just received it since today, and from how it works I like the new UI interface more 
The performance seems smilliar as to the flint, wireguard is aswell very fast 200mb/s down and 240mb/s up with Mullvad (my max speed is 200 down, 200 up), I also really like the new vpn wizard.
I also tried vpn policies these seem to work excellent (not tested yet with more different ip ranges).
the temperatures are a little hot for me but I think that has to do because of the cpu 
, measured 70c with collectd-mod-sensors and is very silent its still acceptable I think(?)
as for wifi I seem to get smilliar speeds as that from the flint.
only bug I found was that the ui became unresponsive when trying to enable nextdns, or other options appart from override dns settings, but this bug seems to be known already.
I also tried samba over lan, and connected my western digital elements with 2tb space and I got around 90-94 mb/s write speed, as for reading I haven’t checked yet I need to find a program to properly test.
as for vlans… I’m not out of this yet they have changed alot in this version of openwrt (in Luci) and I believe the best way to add vlan notation is by using the vlan switch inside the bridge device settings so in br-lan, though I had it working for like 1 minute but all my other lan ports failed to get dhcp my other attemps failed either by my own mistake or the switch isn’t really working, Edit: DSA works fine aslong you create the vlan device first and for lan you create a seperate vlan device with id 1, this video shows it very well: VLANs in OpenWrt 21 - YouTube if you try to let the bridge to create it for you then you end up locking yourself or if you do it on the port you are currently using.
only luci bug so far: adding vlan ids in the bridge the save button creates dupes better just refresh page after clicking it.
so far the router works really stable and im really happy with it 
edit:
I’m on beta4