[itsme]

@Bronz: 
"Embedding annotations also doesn't help so much, because the annotations become ineditable"
Wrong. Annotations embedded by MobileSheets into a PDF can be edited with a common PDF editor. I checked that with PDF XChange Editor V 2.5, others should also work.

"find or list all documents with annotations (or recently added annotations)"
Has been discussed already here: https://zubersoft.com/mobilesheets/forum...p?tid=3415
You can find a working SQL query there. But yes, a filter in MobileSheets would be convenient.

"MS ... is more like an image viewer with an additional database"
First of all MS is a feature rich database, thoroughly adapted to the spedific needs of musicians of many (all?) genres.
Furthermore it does a great job as a viewer and editor for PDF, ChordPro, TXT and many kinds graphics files

"can't see the advantage of leaving the PDFs untouched"
- you have the choice to share your PDFs with or without annotations with fellow musicians
- you can have different layers of annotations in a song and switch them on and off as desired
- you can use the same PDF for several versions of a song with different annotations, e.g. to be used for different bands
...