It's not HoH versus AoH so much as arrays versus hashes. There are places where arrays make sense and places where hashes make sense. Sometimes the choice is hard because neither is quite right, but most times asking yourself a few simple questions will show the way:

• The data naturally comes as key/value pairs: hash
• The data naturally comes as a series of values: array
• I need to keep the elements in their original order: array
• Key information must be unique: hash

It is easy, although not as common as you might guess, to have incompatible answers to the questions, but very often the choice of appropriate type is pretty obvious. Note though that making the wrong choice often leads to very bad code as you try and work around the issues created.