I did my OW with PADI and everything since with SSI. PADI required everyone to purchase printed materials (in 2013) individually
To clarify:
I can't speak for 2013, But PADI have do E learning for courses where all your theory is done on line (Certainly from OW through to Instructor) . Course costs are generally split between cost for course and additional cost for course materials or E Learning. Personally I prefer hard copy rather than sitting in front of a computer. But everyone is different. Not all specialities are covered by E- Learning.
PADI {snip} was more strict about the instructors following a script. Ours went a little off script one morning to teach us about BP/W, but otherwise you had to do skills in a particular order
Not so, I'm free to teach students in BP/W as a PADI instructor. I'm careful how much gear information to give to students only as not to confuse them during OW. But I'm happy to introduce them to other gear (since I have BP/W's jacket, Side mount of my own). I don't follow a script and impart as much info as is requested - again without confusing the students
The actual skills for each lesson are indeed written down and the lessons take a logical order building on each other. The order I get students to perform the skills within the lesson is up to me. We do have flexible skills, which can be done at any time (after a certain point) too