I like the look of the presentation and the active teaching method adopted. I also like the way Savov gives out the definitions and the facts as a pdf but keeps the exercises, investigations and examples for the paid version - the exercises are the value added in Maths in my limited experience.

I just bought the paper version off Lulu (I like being able to read and scribble and then go on the computer for the computational exercises). And now to set up SymPy on Debian...