Advantages: They are a cake - Even giants like them.
Disadvantages: They are NOT a biscuit.
I can't go past a box of Jaffa cakes without eating one, then I will go back and eat another, then I might go completely out of my way, as I traverse around the house of an afternoon, just so as I can help myself to another.
And remember they ARE a cake, not a biscuit, as Mcvities had to prove in court.
When they went to court, Under UK law, no VAT was charged on biscuits and cakes -- they are "zero rated" (and this is probably still the case). However, chocolate covered biscuits ARE charged VAT. Although they are the same size and shape as biscuits, McVities argued that the Jaffa cake IS a cake. The criteria for differentiating between a cake and a biscuit is that biscuits would normally be expected to go soft when stale, whereas cakes would normally be expected to go hard. And this indeed was proven to be the case and that Jaffa cakes were indeed just miniature cakes.
But this is my favourite bit of this story:
In defending its classification of Jaffa Cakes as cakes, McVities produced a giant Jaffa Cake to illustrate that its Jaffa Cakes were simply miniature cakes.
How I would love to have seen that Giant Jaffa Cake!
Perhaps the Jaffa cake people might do special BIG Jaffa Cakes just for Christmas.
Summary: Jaffa cakes are good for your soul
Image by Flickr user kevin (iapetus), used under the creative commons scheme