Sue me, Behringer, but this is an obvious copy of Mackie's Big Knob Studio+ (or is it the other way around ? ;-))
There's one feature making it better, though: the VCA. The pot in my Big Knob Studio+ started crackling after only a few weeks, because it was without VCA. That's not as bad as Behringer's cheaper models (without VCA), which started crackling after only a few days, but at least this one sounds clean - for now (I've had it for six months).
Now I have two bad things to say about it:
Strangely, the jack sockets don't seem fastened to the chassis, unlike in Behringer's cheaper models. I'm afraid they're just held by being soldered to the board, but I'm not going to open it to check that while it's under warranty. In my experience that would make them more fragile. Since I'm not swapping cables around, and I don't let them hang with all their weight, I hope this won't be an issue.
Also, compared to the very similar Mackie Big Knob Studio+, the buttons are much less comfortable to operate. Hitting two buttons simultaneously to A/B compare sources or speakers, you can be sure to miss every other time. That's really annoying.
So, what's worse? A crackling pot, or frustrating buttons? I really can't decide.
As for sound quality: I haven't paid attention to it very much yet. I know the model below this one isn't very transparent (I actually like how it colors the sound, but it's still something you don't want from a monitor controller), but I don't know about this one.
I can only say this: when used as line inputs, inputs 1 & 2 aren't particularly noisy, while they certainly were in the Mackie version. All other inputs are all right in both models.
I can't comment on the USB interface, since I never use it.
UPDATE: After only 6 months, the bog knob became so dirty, or used, or both, that you could hear it even through the VCA (of course it doesn't crackle, but there are drops in level across the course). Also, there's now a L/R balance issue in one of the inputs. So, my final and informed verdict is: piece of crap.
