@PeterSommerlad@mastodon.social looks like 100% Packt, so ... whatever quality the authors have put in. I don't have a high regard of Packt as an editor-publisher, but some of those names are capable at writing good books by themselves. I recognize only Patrice Roy, Marius Bancila and Fedor Pikus - but that's still 4 books, and at that price that's *still* a good bargain.