Annotations from one are visible in the other so you can use both.
The biggest advantage of Highlights is that it can create a separate HTML/PDF/Markup document with all of your annotations as excerpts; it is a lot easier to review this way than DT3 annotations where you need to select each annotation and have it move to the corresponding page.
A very nice feature in Highlights is that it can export a freestanding HTML or PDF document (or other formats) which shows excerpts from your document with the annotations and also has embedded x-Devonthink links to open the original document in DT3. This degree of integration with DT3 is rare and arguably achieves capability notably beyond that in the default DT3 annotation app. You do need to subscribe to get this functionality ($3/month, $25/year), but if you were to stop subscribing your existing documents/annotations would still be fine.
Thank you, this is very useful to know. I use Pdf annotations quite frequently in DT and copy them to my note in Obsidian. I will explore if this app can improve my workflow.
I think a picture is worth 1,000 words in showing the difference. Highlights gives a much better sense of the original content in its summary. More specifically (and ironically) the Highlights app includes all forms of annotations in its summary, including images extracted from the original document. But the DT3 summary literally includes only text highlights, not images. [** You say that DT3 annotations are summarized in one separate document. Maybe you can teach me something - how do I do that? My understanding from past discussions including this one Exporting annotations with details to RTF or Markdown (get to Tinderbox) is that such a feature has been discussed but does not currently exist. ]
