Personally from experience I like Excel better. Concise covering of the syllabus dotpoints, a good set of HSC exam styled questions to consolidate your knowledge, and not too heavy as opposed to other textbooks out there. I find that whilst ATAR notes has good topic test books which part of the questions have originated from them, some of their complete course notes have either gaps in them, don’t fully address the dot point to a satisfactory extent, or can be hard to follow along with at times. Hence I wouldn’t be too dependent on ATAR notes. However as you’ve asked, yes this is subject independent and also from personal experience. I have all of the ATAR notes course notes and some of the topic tests for my subjects besides Science Extension (nothing released for that as of yet), and I also have the HSC survival book from them as well. I found the English Standard book useful and I am still reading it as of now. Whereas with Chemistry, it didn’t explain parts of Organic Chemistry well so as you said it depends on the subject.
If you’re looking for a more extensive syllabus dot-point focused textbook, the "in Focus" series or Pearson for the sciences are really good. For maths I’d recommend either Fitzpatrick New Senior Maths or Cambridge (or Terry Lee's book if you can get your hands on it).
Hope this helps.