Very good for the money. Obviously, no one expects to have bought a Nakamichi with the well-known quality of the old ones. However, it is quite good. The Bluetooth connection works very reliably and the SD card works more reliably than the USB.

January 2025: It gave up the ghost after 6 months...
I will update after the electrician - installer checks it, in case the sound system is not to blame.
In the end, it just needed a good reset, which is done by unplugging the power connector for a few minutes. After that, it came back and works normally again.