Highlights vs Skim

Highlights is a PDF reader for research that turns PDF annotations into notes, available on iPhone, iPad, and Mac. Its free plan supports reading and annotating PDFs, merging annotations, editing PDF metadata, and Handoff. Notes can be exported as Markdown, TextBundle, HTML, WebArchive, or PDF, or sent directly to supported apps including Evernote, DEVONthink, Ulysses, Bear, and Keep It. For scientific articles, Highlights can find DOIs and retrieve metadata; it can link to a PDF on the device if the citation has already been read. Built-in multilingual OCR extracts text from PDFs without searchable text, with processing done on device. Smart Copy outputs copied images as PNG, tables as CSV, and citations as BibTeX. PDFs can be stored on device, in iCloud Drive, Dropbox, or another sync service, while annotations use standard PDF annotations. On macOS it integrates with Bookends and Papers. The free plan is available alongside Pro at $4.99 a month or $29.99 a year. The maker describes the app as intended for students and researchers.

Skim has no write-up on Specifiction yet; its figures are above.