Hi,
Here is the report on my The Loudspeaker 3 build:
I finished these speakers in June 2022, but I really wanted to do some long term listening before writing this report. It takes time to understand what you hear.

The build: 
I opted for a two box solution to make the build a little easier and to be able to move the speakers by myself. Actually I removed the 15" woofer when I moved the bass/tweeter cabinet because this is really heavy stuff.
Cabinets: 21mm birch ply. Coated with polyurethane lacquer.
Front panels: 24mm birch ply. Coated with Duratex.
Internal bracing: 15mm birch ply.
 
The sound:
These speakers are crazy good! They convey the sound of the recording studio or live venue in a perfectly natural and effortless way with all the scale and power that the music demands. Simply amazing! One of the first things that struck me was the decay of instruments and voices.. It is like it never ends. 
It is great to have the possibility to adjust the tweeter level and bass response for different room conditions. In my room I lowered the bass level 2db from default to get a good balance between the drivers. 
I will not take up your time dwelling on in the usual hifi lingo. This is a complete fullrange speaker. Period.
 
The source:
These speakers are like large studio monitors. If you feed them with a poor source you will not be happy. What comes in, comes out. So I really advise you to get some really high end front end gear to partner these amazing speakers.