***NO SPOILERS***
Turns out I didn't like 2 things about Rogue One.
The score was ordinary as hell (you'd think that at the height of The Galactic Empire, the Imperial March would be all over the place..) and the Title Card was rubbish. For a franchise that pretty much wrote the book on awesome graphic design for film, with some iconic typefaces to draw from directly or inspiration from, when Rogue One is displayed it just looks bad.
Still, if the music and the font used on the title card are the only detractors, that says a fair bit about the film itself.
The worldbuilding was AMAZING. Getting a feel for what life under the polished bootheel (yes, the polish their heels) of the Empire is like was something I'd wanted to see ever since I was a kid. Seeing the Rebel Alliance Rebelling (that will make more sense when you see it) was really awesome, and the ending... the ending makes you want to buy another ticket and watch it all over again while at the same time makes you wish they were screening A New Hope immediately afterwards.
If you liked the original Trilogy, do yourself a favour and watch Rogue One on the biggest screen possible.