General

Special Mastery Book?

Well there was another thread about this, but there were maybe 4 responses and not many opinions or explanations, so....
I hit 70 and got the maple admin quest saying I can get a free mastery book.
Which one should I choose? (In other words, which one is most expensive, and thus, most "worth it"?)

Illusion 30
Flame Wheel 30
Magic Mastery 30
Blaze 30
Dark Fog 30
Soul Stone 20
Blessing of the Onyx 25

OR (but more than likely not)
Mystery Mastery Book