Behringer Amp800 V2

TL:DR : Build quality below what I feel would be a 69€ headphone amp, the amp does not offer a real signal gain.

Currently building a small podcast room, I was looking for a cheap headphone amp so that all the guests/hosts have their own direct monitor coming from my main audio mixer.
As this is ( at the moment ) not for "professional, aka make money with it" use, and money was tight, I decided to buy this Amp800 V2 from Behringer, which has just launched a few weeks ago.

Let's start with the build quality. I was hoping to get at least a partially metallic box like they have in the UMC line of audio interfaces, but no, you get a 2-tone plastic box, albeit a somewhat sturdy feeling plastic box.
I know that the mini series of Behringer products isn't meant to be rack mounted, but I feel they have missed the opportunity to make it "rack ready" by shaving a few milimeters of height, qs the Amp800 is 49mm thick.
All the rotary buttons require a similar force to turn, I am not sure about the usefulness of the input balance buttons, but if you needed them, they are present, and lock at the center position ! The push buttons have a little more play into the plastic housing than I'd like, but I've seen worse. The same can be said about the VU-meter's LEDs, which means that the unit makes a rattling sound when you pick it up/move it a little bit fast. ( This will soon be a non-issue for me as I will permanently attach it with 3D printed brackets )

But for me, the biggest downside is the amp by itself. It is just not that powerful. Compared to the headphone output straight out of my mixer, I have to crank both the input and the output levels of the amp to the max to get about the same output volume as the headphone output of my mixer at half volume. ( all of this tested with the amp hooked up to the balanced monitor out of that same mixer ( Yamaha MG16XU ), with the monitor level also set to half of it's scale. ) so I feel that there is no real signal gain.
But at least you get 4(8) independent headphones out and no loss of power as you add more and more headphones ( tested with 4 headphones ranging from ~40 to 300 Ohm )