Sound:
The sound quality is not acceptable to me. Especially the piano samples sound highly compressed, show artefacts and are muddy. The DAC sounds flat and distorts easily.
Handling:
The unit doesn't have any direct possibility to be controlled on the device. Changing sounds or banks e.g. must be done by MIDI commands directly. I do not see this as a problem, it works as advertised.
BUT: The unit always returns to default settings on power up. This renders it unusable for the possibility to (pre-)configure it (e.g. by an app or external controller), packing it up and using it as a simple and fast expander in a rehearsal or on a gig.
Features:
Features are ok, the basics as excepted, with flexibility to play different sounds on different MIDI channels.
Quality:
All in all quality (as in build quality and sound quality) is not convincing for what it is advertised - especial taking the price tag of over 400€ into account.
After in-depth testing I returned the expander.
I probably would have kept it for some of the non-piano sounds that are reasonably good if the price were maybe around a quarter of the actual price.