Readwise Reader looks more mature as a product and seems to be geared towards learning, thanks to its Daily Review dashboard for reviewing content in Readwise. (View Highlight)
Reader also provides a Ghostwriter feature for creating AI-based article summaries and Q&A flashcards to help you memorize content. (View Highlight)
There is an Omnivore plugin available for Obsidian to import your highlights and notes (manually or scheduled) into Obsidian, based on custom queries. This allows me, for instance, to tag certain items in Omnivore with a label ‘ToObsidian’ and then import just those items into Obsidian. But best of all, I found that I could not only import highlights, annotations and metadata, but also the full original text by adding the {{{content}}} parameter to the Article Template field in the Omnivore plugin settings: (View Highlight)
If you like a clean interface or want to review your reading matter for learning purposes, the Daily Review feature in Readwise Reader may be a big bonus to you. If, like me, you want to import the orginal source text together with your highlights into Obsidian, you may prefer Omnivore. (View Highlight)