The biggest problem I had with this movie is that I couldn't understand how if fit into the X-Men timeline. Things happened that would make previous events impossible. I was thoroughly confused.
Outside of that one thing, Dark Phoenix was somewhat entertaining. I have not seen all the X-Men movies (maybe that contributes to some of the timeline confusion) and I was not familiar with some of the characters. The fight scenes were well done and an excellent display of the various powers of the mutants.
Jessica Chastain played a weird character that was searching for Dark Phoenix. Jennifer Lawrence reprised her role as Raven/Mystique and James McAvoy plays Professor X.
With Disney acquiring Fox, the X-Men are now under the same umbrella as Iron Man and the Avengers. Hopefully, this will improve any future X-Men movies.