The sound is clean. I honestly don't know what the bitrate/sample rate is but the audio is clean. It seems to handle line level and instrument level without issue.
I was worried because I have the 1010music black/blue boxes which record clean but due to ground issues can sound noisy on monitoring/output (depending on how they're plugged in for power). I thankfully don't have the same issue at all here.
I'm mostly playing around with the synth modules right now and (in the picture) added the VCA at the end before passing into another pedal to bring it back to instrument level. I think there's a mixer module, but I'm still exploring.
The included reverb IRs sound great. It was not the reason I bought it, but after going through them, I know I'll be using them.
I don't know about the cabs yet, but they're IRs too so even they suck (which I doubt) they're replaceable.