I decided to pick one up today on the way for an overnight work trip.
It’s pretty good so far into rather crappy headphones, but I did notice the hiss issue, mainly in the clean Twin model - it appears gradually after letting a note or chord sustain, and as it increases in volume, lasts 2-3 seconds before cutting off - even if the note is still sustaining. Really kills that particular model. I don’t know yet if it is on the original firmware, or if upgrading the firmware will be the remedy...not a deal-breaker, as I like quite a few of the other models, so I have no intention of returning it.
That's unfortunate with the hiss.
I also get hiss on my GT40 but have learned to live with it.
You can still jam along to an amp3 player and not hear it over the music.
It does limit the amp but it's not the end of the world