I tested this amp with the wireless transmitter on classical guitar using both piezzo and usd pickups, both from K&K, for jazz and classical. fingerstyle.
The features, portability are great, easy to use, the app works great as well. The mic models really do sound different, and create colours that are fun to explore.
I ended up sending back due to 2 issues that mattered to me, but they might not be that important for everyone.
the volume is quite low, made it hard to be useful when playing with other instruments, probably its really meant to accompany your singing.
there is a small but clearly audible hiss at higher volumes, and since its not very loud, i did need to use the higher volume. now, normally my acoustic setup is really dead silent, zero hiss, so not everyone might be bothered by this, but if your playing, music includes breaks, silent parts, it can matter.