In my little metal world, Brutal Assault in the Czech Republic is the best equivalent. Held in an old fortress from the 1700's with a fair amount to see/do/eat/drink. Sadly cancelled this year - one of many casualties on my schedule this year.
Always fancied Glasto for the culture/arts aspect of it (if certainly not the music), but never been motivated enough to jump through the hoops required to get tickets.