Finally got around to watching this last night. Have to say that overall I enjoyed myself, although I was quite disappointed with the final third of the film.
I really like David as a villain. It helps that Fassbender is a damn fine actor, but I appreciate the time and effort that's being taken to build him as the most important character in these new films. His motivations and methods feel quite scary and unique, while remaining true to themes that have been present in the franchise since it got started. I actually like how they handled the situation between him and Shaw, leaving a lot of it unspoken and up to the viewers imagination, only to then explain some of David's macabre experiments and hit us with that one shot of her dead body. It was an effective gut-punch, and a good bit of psychological 'horror' (to think that all of Shaw's hope and her quest for answers came to nothing in the end but despair and an horrific death).
The initial sequence after the Covenant crew landed on the planet, through the first infections, up to the explosion of the lander, was fantastic. I loved how the characters were properly scared, confused and making mistakes as the blood and gore suddenly burst out all around them. That's exactly how that kind of situation should play out, and it was very well done.
On the other hand, the entire end sequence(s) was/were a big let-down for me. The Alien attacking as Tennessee picked up the survivors played out in a completely unrealistic way which destroyed any tension or excitement the scene could have had. Then the 'fourth act' back on the Covenant was far too rushed and easily tied up and so, again, devoid of any tension.
I've just accepted these films for what they are at this stage, so I'm looking for the good in them. I'm looking forward to what I assume will be the final act of this new take on the Alien franchise. It's been something a bit different, at the very least.