Agree with that kayakamina. Much more of a challenge and all the more enjoyable for that. However, I do think it's helpful to have a reasonable mix of 'easier' and 'harder' puzzles(though one man's meat etc..) as the former can encourage less experienced solvers to persist in the arcane art.
Is it that challenging? I didn't find it too difficult, and it's possible to solve it without taking the trouble to work out or reference the quotation (though I did, just to be sure).