The footswitch turns it on/off only after you press AND release it. This is very weird and can mess up switching during a gig. Also if you long-press the switch it changes mode, so one more thing to go wrong during gigs.
The "output" knob achieves unity level at a very narrow range around 8 o'clock. A little lower and you can't hear anything, a little higher and you're too loud. I find it hard to fine-tune to unity level, most of the range of the knob is useless to me.
While trying to turn it on/off and switch modes, I somehow entered a mode where the pedal was stuck in bypass mode, nomatter if I turned it on or off. After removing and re-placing the power supply it went away and now it works.
It makes a poping sound when engaged, not very loud but it is there. You can't hear it mid-song but it is audible e.g. between songs or during quiet parts. It's my only pedal that does this (out of 40+ pedals that I have).
It sounds good, quite similar to other klon-based pedals I've had. Comparing it to the silver and gold Archers I had, the Nux has more compression even on clean-ish settings.
So get it if you want a good klon sound at a low price. Think twice if you want to use it live/professionaly.