I loved it. I think it edges out A New Hope in 2nd place after Empire. It feels like it was made for me: A movie made for the now-adults who were (and remain) huge fans upon seeing the original theatrical releases 34-40 years ago. If this is how these stand-alone Star Wars stories are going to go, I hope they get churned out routinely and are more adult, more dark with their focus market being the old fans like me.
One of the reasons I rate this movie so high because its rewatchability is excellent. I loved The Force Awakens the first time I saw it, but it hasn't held up well upon additional viewings. I suspect that's because Episodes 8 and 9 need to tie up many loose ends so I'm withholding final judgment, but right now it's a flaw that Rogue One doesn't suffer. Rogue One is actually better the 2nd time watching it as the first two acts don't drag as long as they did upon the first viewing, knowing where the plot is going. And the third act is arguably the best in the 8 movies, up there with the Endor/Space/Emperor's Chamber battle in Jedi.