In that case the Marantz will be ideal.My problem is that the system will be used by my parents and they dont want any app-based controls. Else WXA-50 would have been a no-brainer. Also, they dont want streaming.. only local playback from USB (primary device), then Bluetooth and occational CD playback.
Only callout - not easy to navigate a complex folder structure, for parents generation.
Maybe keep all the music files in root folder, or have a very simple folder structure.