It's the closest you can get to the actual SMiLE in terms of original takes. And although it's clearly missing some sections of songs (vocal parts, mostly), it feels like a complete album, and an incredible one. Plus, the bonus tracks really give you a notion of how complex the making of the album was, and the many different paths its music could take.
Do I need another copy of this record? No. HOWEVER, I must have it! SMiLE is definitely my favorite Beach Boys record after the obvious Pet Sounds pop masterpiece. It's getting a lot more known now, which is fantastic. This release should help get the music out to more people. Also, the box lights up, which is awesome.