I don’t know about the value of libro.fm… Seems to me that the monthly subscription is the price of a physical book and you only get one per month?
I get a much better deal with my city’s library which offers a large catalogue of audio books for free. It’s not owning, it’s borrowing like you would from a library but at least it doesn’t cost anything.
If you look at the author’s bio, it seems like they’re more of a hardware peripherals tester than a perf tester.