Currently RHLS offers both:
PDF (claimed to become legacy) and eBooks.
To see the future I tried eBooks as well. My experience was this:
I gave a try and was badly disappointed - not saying shocked. Neither on the Red Hat Bookshelf web frontend (on my reasonable 24" screens), nor on an iPad Pro 12.9 5th Gen, I was able to read the graphics (e.g. I can't read IP addresses (simply too small and no zoom available), plus some graphics appeared faulty as a such), nor I was able to understand the overall content and essence out of the course. The pages simply show not enough content and to get an overview! Even the tables of content sometime spread across many pages... Even though a big reader could show the content of a letter/A4 page the content has been spread over the double number of sizes. So flipping back and furth with the laggyness of the app makes it really hard. Resp. impossible to get the essence out of a technical drawing when poorly readable plus the legend splattered over another few pages.
Benefits I see in PDFs (and paper/physical books):
I'm used to PDFs (a reliable format) and like it - such as printed books. Since the RHLS doesn't offer printed books, I also to print them on my own. Prints gives me the opportunity of carefully reading offline and taking instant notes by pen. And for topics of higher complexity (that's why people buy the courses!) it's possible to put the legend beside the technical drawings. It also keeps the screens free for the course videos and labs.
Reading from paper and taking notes by hand is also well proven learning strategy. And reading unbothered from distractions and not worrying about battery life or devices getting damaged or stolen. Also before Exams, for me, it's much easier to get a last overview to the crucial things by flipping though the pages an jump and stop at marked pages and notes. Or later reference when I need to refresh the memory for an upcoming meeting or job. Searching the PDFs allow me to get the right book out of the shelf and read it either in Acrobat or get a book to do it traditional way.
My conclusion:
For professional reasons I need to maintain my Red Hat certification. So, I'm quite worried about what I see the course material might go to be like. I already approached the Red Hat support in charge (RHT Learner Experience) but I'd like making my voice heard also here - in hope the option of (printable) PDFs will not be retired.
