Given my experience with WiFi 7, and the availability of kit which can make use of it, go for WiFi 7 if you have money to burn. If you have kit which supports 6E, buy something which can handle 6E well. When that router goes to Silicon Heaven then you might consider WiFi 8 or whatever follows...
Benefits? That's for the omniscient prophet, F__k Knows.... However, I run Merlin for five reasons:
I can.
Bug fixes.
Updates.
There is no 4.
Five is right out.
For me at least, the AXE-16000 works absolutely fine with the Merlin firmware. Had one as my main router, now relegated to being a node since I got a GT-BE98 as the main node (also running Merlin, 3006.102.3_1-gnuton0_beta1). Now I just need my EOL RT-AC68U node (yes, also running Merlin), to...
I've just relegated an RT-AC86U to be an AiMesh node (and moved a printer to hang off it). I've got a RT-AXE16000 as another AiMesh node, and a GT-BE98 (not yet running Merlin), as my main router. Backbone connectivity between them is via Devolo boxes and I'm getting ~1Gbps between them. [I've...