If you are reading this, chances are high you are at least a casual fan of Star Wars. It comes with the territory. Let's assume you've come here to find out how good Rogue One is without reading spoilers. I think I can be of help.
To summarize the story briefly: Agents of the Rebellion seek out Jyn Erso, daughter of the Death Star's architect. They want to use her to gain access to information about that rumored, terrific weapon. When they find out that the Death Star is real, a group of soldiers tries to steal the blueprints to the space station in order to find a hidden vulnerability in the design. If this is not what you expected then...where have you been the last couple of years?
The stakes are high for Rogue One. The first non-saga movie under the ownership of Disney is opening the door for all sorts of possibilities. Next they're launching the first solo character movie (With somebody named Han Solo as the main character? Such perfection rarely is coincidence), then who knows what will be on the horizon? Lando Calrissian in Space Rounders, Obi-Wan Kenobi: Agent of SHIELD? One way or the other, Rogue One needs to prove there can be a proper Star Wars movie without touching the big saga story line first.
Does the movie deliver? Well. Kind of.
During the first half of the movie, there is a slight chance that Rogue One has enough air to breath and tell its own story. Sadly, the first half is the weak part of the film. While of high production value and refreshingly different in tone and atmosphere from the saga movies, the storytelling leaves a lot to be desired. Almost all of the introduced characters are two dimensional and bland. Their motivations often remain a mystery to the audience; their back story is sometimes not even hinted at.
Still, even though we do not get to know this odd group of people very well, they are an interesting and fun bunch. It is too bad that they have to wrestle with other characters for our attention.
Whoever decided that Rogue One needed training wheels made them way too big, too clunky and too heavy. Imagine those training wheels to be elements of fanservice. References to the original trilogy are legion. This would only be mildly annoying if the methods used to give us the impression that Episode IV is breathing down Rogue One's neck were not so close to necromancy at times. You will know what I mean.
The plot stumbles through the first half of the movie like a drunkard who knows how to get home but just cannot get the key into their front door lock. Having a great cast at least means that the drunkard still looks competent while fiddling with their keys.
When our--for a lack of a better term--heroes arrive at the point of no return and decide to start their mission, the movie rolls up its sleeves and shows us just what the people at Lucasfilm are capable of in terms of action and effects. We get to see the best space battle ever put on screen, the grittiest war scenes of the Star Wars franchise and a finale that gives us something many of us did not know we wanted.
Is it a fun movie? Oh yes. Does it have flaws? Quite a few. Will you regret watching it? No.