I saw this in the cinema originally and I didn't like it. I couldn't quite put my finger on why - there was so many hidden meanings I doubt my brain could comprehend everything. Although there are some scenes that you have to roll your eyes at for the sheer stupidity - for the most part it is an enthralling film. It isn't a sequel or prequel, it's more of a spin-off (you will see why when you watch it) it's not big on scares, there's a few jumpy moments.
Michael Fassbender is the best thing about it. Watch this film with an open minded I loved it the 2nd time and 3rd time round - I always seem to notice more and more with each viewing.
It looks beautiful on blu ray however my only qualm with the blu ray release is if you want all the special features you need to buy the 3D version (I don't have a 3D TV) so you'll have to pay the extra 5-6 pound but the special features are amazing so in depth. Everything you could want to know is there.
I will re watch this film with the commentary on. And I'll watch it several more times. I love it, but its not for you if you want spoon fed every bit of information. Do a little thinking for yourself.