I have my Grail right now - BiB. I posted in RGP over four years ago that I wanted a pin based on not just ACDC, but in particular Back in Black. The icing on the cake is the Steve Ritchie/Lyman Sheets design. They are my favorite designers for hardware and software.
I can also say that owning it is not a letdown at all. Especially with the new software load, it's the best pin I have ever played bar none.