When SolidGoldFX purchased and reactivated the Diamond brand, I bought the Comp/EQ right after it was released. It never left my board since then (almost a year now). For one or two years prior to that, I've been using Mooer Yellow Comp that's based on Diamond Comp, and I picked it over a lot of other, more expensive compressors that I've tried.
If you're into funk or country, and you want to "squish" your guitar signal using very pronounced compression, this pedal can do it, but it's probably not your best choice. What this pedal excels at is taking your tone and making it 10-15% better. On top of that, it has two quick "problem solvers" in form or Tilt EQ, which is arguably the most powerful kind of EQ, allowing you to make your tone brighter or darker without changing its core characteristic too much. The added mid-boost around 800 Hz Is amazing in my case because I prefer transparent drives like BD-2 or Greer Lightspeed, and that one Mids knob can give them a Tube-Screamer-like mid-hump, which they don't inherently have.
Diamond Comp/EQ might be my favourite pedal of all time.