I would given a rating of 5/5 but the grimoire was so darn good that it makes this book seem not complete. Which it does actually mention in the book that magic is rare and that the focus is on swashbuckling, adventuring and similiar things but not on being a dedicated spell caster.( I did give a 4/5 though)
That said it does go into some detail on using special powers as spells and could easily be enough for most people to design a pure spell caster and enjoy the game as is. Other powers whether they be background or talent will allow you to design any kind or character in a low tech setting.
With a little work on the users part you could also make characters for other setting as well(super, cyberpunk, modern, etc.). by applying the same rules you would design a fireball,lightning bolt or ice blast you can apply a gadget limitation and create a blaster, super power or any other form.
I am actually upset that I bought the old Bash UE before purchasing this book as the rules are slightly different for some things but can make a huge impact on the game(how you soak damage and if enough wounds damage is taken at 1 time you can suffer dice roll penaties). Plus it is easier to adjust a game to a supers campaign set in a similiar world to ours from a low tech setting than vice versa. I am also starting to design for a sci fi setting as adding tech weapons are not that hard and making a sailing vessel into a startship is just as easy as adding a a couple of vehicle enhancements.
As a long time player of DnD I like the general setting presented in the book but with the simpler rules and fast action of the BASH system I am a convert to the BASH engine of RPGs for other genres as well.