This is basically the 6 disk Alien Anthology set, plus the Prometheus 3D Collectors Edition set paired together in one 9 disk Amaray case, together with various other bits of tat in a rather nice box.
I agree with others that as a concept this box set is pointless, but since both the Alien Anthology set and the Prometheus set retail at about £20 individually, this set becomes worthwhile if you don't already own the Alien films on blu-ray and if you get it cheap enough.
I have none of these disks on blu-ray, and acquired the box set for not much more than either set individually. At the price paid it was a fantastic chance to buy the Alien Anthology and get the Prometheus set for free or vice versa. I was planning to get the Alien Anthology set anyway, so for me it was the former rather than the latter. The Ridley Scott notes in the Amaray case are the exact same notes as in the Alien Anthology, it's just got 3 extra disks.
The Amaray case with lovely slipcover artwork sits on my shelf in the very spot where the Alien Anthology would have sat, for about the same price.
As for the tat, that's all down to if you like that sort of thing and if you want to wear the t-shirt. The little booklet has some nice artwork and I've squeezed that into my Amaray case, but the rest remains unwrapped in the larger box and now resides in my attic never to be seen again.