I use this in my control room. My soundcard is a RME Hammerfall DSP Multiface II and my monitors are KRK - VXT8. The C-control is a cheap and "practical unit, but should I upgrade this to something better...?
I had a C-control and got rid of it. It does degrade the sound noticeably. I set it to unity gain and patched it in and out to test. I went with the Presonus Central Station as my upgrade. While it's not a perfect unit, I'm pretty happy with it.