I buy mostly ebooks for technical stuff, no need to kill trees in fashion driven industry, so I take advantage of Pack deals when they come around.

Yes there are plenty of books that aren't that good, but there are also quite nice gems there.

Oreilley was good in the golden days of UNIX, nowadays it is just like any editor.

The few NoStarch books that I have, with exception of the Rust book, all seem quite superficial to me, more towards begginers.