Now that a few people have seen this, I thought we should have a place to talk about it without worrying about spoiling it for others.
Overall, I thought it was typical JJ Abrahms - thoroughly enjoyable if you don't spend too long thinking about it. It was also typical that to him 'homage' apparently means 'rip off'. If you're feeling charitable then he took the spirit of the original and updated it for a new audience; if not, he tried to re make ep4. Still, it was a solid piece of filmmaking which was really fun to watch.
The biggest problem I had was that I didn't understand the stakes because the sides weren't explained properly. At first I thought that The First Order had simply picked up the Empire's reins, then a Republic is mentioned which is apparently different from both the Resistance and GO, whilst secretly supporting the former's guerilla war. So, is the Galaxy now like Korea with the Republic and FO in control of different parts at an uneasy peace?
If so, surely the FO's Death Star ripoff would re-ignite a shooting war? Surely a galaxy-spanning Republic wouldn't have their entire fleet sat in one star system? Why didn't they throw their support fully behind the Resistance? I feel that these were plot holes which would have been easily fixed with a few lines of dialogue and maybe a map of the state of the Galaxy somewhere near the beginning.
I had other issues, if course. How did Rei go from not knowing how to fly the Falcon to threading it through a downed star destroyer in seconds? How did Finn suddenly know how to fight with a light-sabre? What was the point of Capt Phasma?