I've never been to the Edinburgh Festival.
To be honest, it's not at the top of my bucket list. It's not even on the list.
I'll go one day, but it'll have to wait until i've visited the Caribbean; Canada, Le Manoir aux Quatre Saisons and a multitude of restaurants/places to numerous to mention. (Now you're all thinking i'm a heathen - i'm not, honest, just got other fish to fry.)
If you are heading North for a bit of culture and you keep kosher, there's a treat in waiting for you courtesy of the Edinburgh Hebrew Congregation.