I like unique cases, such as the "helmet" cases for Iron Man, Transformers, Terminator, etc. The "USS Enterprise" ship for the Chris Pine reboot is cool...the BDs go INSIDE the saucer section! Yes, these may not conform to the rest of your BDs or fit the shelf easily, but they're unique and cool.
Steelbooks and the copycats are getting played out and are NOT unique or cool anymore. When everyone has it = not unique, not cool, not special, just NOT.
Definitely do NOT use the case like the recently released Robotech: The Complete Set..20 dvds stacked on top of one another on the insides of the covers/back and on two "pages" in the middle. The plastic tabs holding the "pages" so that they can be "turned" like a book are weak and already broke in shipment to me.
Individual BD cases within a beautifully decorated box is fine by me, like the recently released Gatchaman: Complete Collection on blu-ray.
But I wouldn't object to four "helmet" cases of Priss, Linna, Nene and Sylia.