OK guys just got back from seeing it... I'll put spoiler tags in as needed.
My overall feeling is that it was a decent film, but had some flaws, and as an Alien fan a few things really pissed me off.
I felt that the start of the film, up to the landing on the planet was all solid stuff, the characters were all decent, and even though I didn't know some of the names no one came across as extra or unlikeable ala Prometheus.
The first obvious flaw for me was the going to the planet and not even a mention of a breathable atmosphere etc, or any acknowledgement of the forests everywhere etc - this may have been trimmed out I guess, I just had to kind of accept this was missing and say "hey it's sci fi" and let it go.
The neomorphs were pretty cool in their own way, again I thought the acting around them was very well done - some great reactions from the crew etc. One lady specifically does a great job of being scared out of her mind. The first one or two scenes the CGI was pretty bad though, after that it recovers somewhat.
In some ways my biggest problem was with David, he's got a God complex that's for sure... but I felt the "why" was missing a bit from it all.
There were some interesting scenes with him and Walter, but they didn't quite pay off for me, it was close, with the creation stuff, but didn't quite hit the mark. This movie does make you hate David though, he is a huge douche.
Oh and for the record (MAJOR spoiler)
f**k David inventing the Xeno, I mean really Ridley, f**k you for ruining the mythos
The final act of the movie is pretty predictable, it's still enjoyable though, it was pretty tense and I was overall happy about it.
On the Engineers (minor spoilers):
Basically written out... WTF why is no one from the crew saying "f**k me an alien civilisation, how amazing!" I thought it was a travesty that Scott has f**ked the Space Jockey with the big bald human engineers in a suit and then not follow through with them, I could forgive it if he has gone more into their mythos, but it's completely clear to me that engineers are now an abandoned concept
Alien life cycle is AvP fast.
Alien vision ala A3, which imo was completely unneeded
On Shaw (big spoilers):
Again a complete waste, she's just been written out. The cool biomech prop on the front page is not in the film, there is a dead Shaw prop but she looks a lot more normal, apart from her chest is open (it's the big open chest we saw in old set pics)
Overall as I said to my GF going in I expected this to be a kind of reboot, but what Ridley has done is write off all threads of Prometheus, further screwed with the Alien mythos, and elevated David. It's kind of like he knew Prometheus was a bit crap, and decided to axe all the bits that didn't go down well, and make the story all about the popular supporting character.
What we have in the end is a good film on many levels, but on the Alien mythos level (which we all care about) it's all over the bloody place. Now don't get me wrong I still enjoyed it, but as an Alien fan more and more I'm seeing this as a spin off series which can be enjoyed for what it is and not a core part of the franchise.
The movie is left completely open for a sequel,
I actually loved the last scene with Daniels
but my advice to Ridley would be this - don't tie it in with Alien, LEAVE ALIEN ALONE. This Prometheus spawned series should be allowed to be it's own thing, and I think we as fans would be able to enjoy it a lot more like that.
To summarise - a mostly well made movie, good acting throughout, decent characters which are all believable, nothing too complex or jarring like Prometheus, shits on the Alien mythos, completely wastes story threads from Prometheus, focuses too much on David. Oh and the music was great - lovely remixes of the original Alien score in places which I loved.
I'd give it a 7/10 for enjoyability, could easily have been an 8 or a 9 with some minor changes and a couple of additional scene to smooth it out. I will be really interested for the deleted scenes on this one.