I saw Rogue One today, and it was really good. I think for their first ever standalone film they did a really good job. You have interesting characters, nostalgia for the earlier fans, and awesome special effects.
I think everyone who loves Star Wars should see this film, but I do have two complaints. The characters are very interesting and likeable, but I with what they did I don't think they gave enough backstory for most of them. Honestly, most were there just so they had a crew. I'm not saying they weren't used, but I would've liked a little more backstory from some.
The second complaint is that there is one CGI character they had in a little too much. I understand that the character was important, but I don't think they needed to use them as much. The CGI was just very noticeable to me, and it took me out of the film when they were on screen.
Other than those two complaints Rogue One is a very enjoyable movie that I think all Star Wars fans will have a great time with. I say you should definitely see this film as soon as you can, and have as much fun with it as I did.