I'll maybe answer a few Q's and share some things having played it a bit and following the development:
1) Yes, this runs better than Arma 2 does on low end PC's. At least it runs better for me. They concentrated on optimisation from the early days of making standalone.
2) This is not the latest version of the game. I've watched a few streams by rocket ad it looks like the media they've released is a few months old. Why? I predict this might be the most stable recent changelist - they release it, see how the servers etc cope, then update it incrementally to get us more up to date without breaking everything.
3) Its totally playable even with this old media.
4) There are bugs. Kerrigan went unconscious after eating a rotten apple, was out cold for ten mins before I logged out. He might still be unconscious. This is either some hyper-real design an I need to find an Epi-Pen to wake him up, or a bug. Someone mentioned above that they were out cold for ages too.
5) There is less killing sight. In the time I've played it I've bumped into maybe 12 players, including 2 pairs of well armed players. They all spoke to me, and I spoke back. One pair asked me to sit down while they looted a shop (that I had already looted), and they all left me alone. Its like the old days, and I suspect most people buying it now want it to be like the old days - myself included.
6) There are some really cool little touches/features. For me it was the books before if you picked up a book it was just a waste of an inventory slot. Now you can equip it in your hand and when you use it, it opens up the book. Theres loads of really old books that are now out of copyright, and you can read them in Dayz.
Looks like Jackie has been playing longer than me seeing as he is better armed than I am with my fucking fire extinguisher, so maybe he can say more. These are just my observations.
p.s. Jackie come to GK ts tonight if you like no doubt me and kerrigan (plus others maybe) will be playing.