Ok, a quick update on my attempts to import the MusicBee iTunes XML into Denon Engine Prime.
In short, it is possible, although your tagging needs to be pretty clean. However it doesn't work if you store your files on a network drive.
There were a few items that caused my import to fail and through a trial and error process I found all the issues.
I did this by making copies of partsof my library and using a portable install of MB I created different XML files which I then tried to import into Engine Prime.
Issues preventing successful import
Some dates were not formatted YYYY
Some playlists had no contents (due to the filter criteria not returning results, or renaming of target directories etc.). Removing these playlists in MB allowed the syncing.
Playlists that were organised in folders did not import, but a flat list of auto and static playlists imported ok.
When non-numeric characters (e.g. A, B, Side A) were present in the track number field the import worked, but no track number data was added to Engine Prime for these entries.
I saw strange behaviour when importing that I now think is due to the files being stored on a network drive. There were times it went through the import process but then reported 0 tracks in the Engine Prime collection. Other times the tracks imported, but then seemed to disappear from the folder they were in previously.
It seems this is due to the way EP handles the relative path to the files.
One final note is that I didn't notice import issues caused by non-ascii characters in the filenames or metadata.