For some time I have been looking for a tube-less solution for playing at home, sometimes loud, but also with headphones. I have tried several products from two notes and even an Ampero II, but I could not get along with them, with my rig they all sounded thin or super sterile or overly compressed.
I bought the Simplifier X out of curiosity without much expectations. I am using it through an audio interface and audio monitors. The tones that I am getting out of this little device are insane, but more importantly, the feel is great. It does clean, edge of breakup, and higher gain quite well, while keeping the picking dynamics.
Most of the youtube reviews that I have seen sound worse than the tones I get at home, I suspect they over use the power amp gain. Which probably means that you will need to spend some time learning how to use the controls. The most representative demos that I have seen are the ones by the actual designers of the pedal, some of them in Spanish.
Totally recommended, it is the first non-tube solution that keeps me away from playing my 5F2a clone. If you don't need the parallel setup, the mkII is probably all you need.
My only complain is that the spring and ether reverb modes are super wet, and they go from nothing to "almost too much" in a very little turn of the knob. Thankfully, the plate reverb has a lot more headroom.