I saw this movie last Saturday without reading any reviews prior to attendance.
I enjoyed it. It was predictable (it was always going to be), but enjoyable.
Far better than the previous fantastic four movie they did (lets face it, that thing was horrible).
I really don't understand why the critics are hammering it so bad, I've seen far worse movies that got much better reviews.
TLDR: Grain of salt, it was decent.
My criticism is solely related to the studios not needing to start again, same issue with Spider-Man. They should have just made a sequel with new people and not worried about cast changes. We know who they are, and we know they aren't the most exciting heroes, so why would we want to see the same story again?