As a long-time educator and purchaser of Arduino-kits at a major educational institution, I just wanted to give my 5 cents.
Pro:
The components and projects look very entertaining and you do not spare more complex stuff such as an H-bridge and LCD-display, great!
Cons:
The book is not available online, it is only in print and i presume you have copyrighted it.
The box in boxes will break if the kits need to be lent to students, sequentially.
Those are my first remarks, if you get closer to spark fun, you'd stifle my doubts, and we'd start supporting Arduino at the source.
However the con's are deal breakers for us.
best / ole kristensen