This is a really useful little box. I use mine as a small mixer for musical directors in a pit orchestra. I feed one channel with band and click track, and the other channel with the cast singing. The mix feature allows them to set the balance between these 2 mixes, which is really useful, particularly in quieter numbers where the cast need turning up. A real labour saving for me.
The unit is well built, though mine already has a few scratches on it. It's not been particularly misused so I wonder if the paint finish is maybe a little delicate. It really doesn't affect the functionality though.
The balance knob has a centre detent, although this detent is slightly misaligned with the legend on the panel. Again nothing big to worry about.
Would be even more useful if it had a 6.35mm jack socket as well as 3.5mm.
Great product. I'll be buying more.