I tried Blinkist but gave up quickly. Their summaries are not high quality. I don't know who writes them. When I looked up summaries of books I'd already read (Deep Work, Startup of You and some others) they didn't match my sense of the book.

I wish someone would fill this niche. There's definitely a need for a good book summarization service. The service shouldn't try to replace the book-read. They only need to help you decide whether you should buy/borrow the book.