Got this new toy in the mail yesterday, spent the whole day today (national holiday here in France) playing with it, and I have to admit I'm impressed!
(and as a former boutique amp maker, I have pretty high standards 😉)
I've already captured 4 of my amps, and the results are quite convincing!
Definitely not the same feeling as standing in front of a "real" amp, but I could very well consider using it for recordings, rehearsals & gigs 🎸
@baronvonj FRFR speakers don't help, I'm actually using the Nano Cortex through my studio monitors. OTOH this difference is logical and basically unavoidable:
* on one hand, you have the basic "guitar -> amp -> speaker" chain
* the Cortex emulates a "guitar -> amp -> speaker -> mic (incl. placement)"
That final bit makes it impossible to replicate the feeling of playing in front of the amp, as every mic has its own frequency response, and its placement can make an enormous change.
A-wai 
Baron Von J