I own a Tone King Imperial Mk2 amplifier, which is by far my favorite piece of gear, but I often practice at night, with headphones on, and I love to sound good even when I'm really just practicing or fiddling around. I have ToneX, I have Quad Cortex, many plugins, but none could give me the feel I have when I practice on a real amp.
This preamp pedal simply mops the floor with the Quad Cortex, ToneX, and every other digital stuff you can buy. It sounds incredible through headphones. It feels great, the response is amazing, the tone is just beautiful. I can use my whole pedalboard with it, even at night, and since it has an FX loop (as opposed to the amp), I can actually shape my tone even further.
I have absolutely 0 regrets for buying this, this became my absolute favorite for low-volume and headphone practice sessions. It really can't get any better than this.