I too rewatched Prometheus not so long ago. True - its not terrible, but not counting avp, Prometheus is the least re-watchable and I kind of felt like I was only sticking through the movie for the Hammerpede and the Medpod scene - then I kind of tuned out again. The engineers are actually annoying in Prometheus, whereas in Alien, their allusion was fascinating. There I've said it - Engineers don't float my boat anymore...
Even the drab looking Alien 3 had more moments I'd want to re-watch from a storyline perspective.
While everything sounds promising for Alien Covenant - Giger inspiration, more creatures, good budget and decent shooting time, I just hope the script delivers. In the early days, the script (and even the title of the film) has had so many reincarnations (like many movies these days). I just hope the script is gripping, the acting is of Charles Dance/Sigourney Weaver/Ian Holm/Lance Henriksen/Glenn Close calibre, and this becomes a movie that I will want to rewatch time and time again in years to come.
Ever the eternal pessimist, I know, but somebody has to be...