There isn't much I can say about this movie without spoiling it for you, so just know that it is great and you must go see it.
One of the best parts about this film are the main characters. All of the characters are great, with the original cast of Luke and Leia being fantastic as always, but of the new cast, Poe Dameron is my favorite of the film. He is way more fleshed out than in the previous film, showing him as more of a smart-ass rogue than a charismatic pilot. He does not feel too much like Han Solo's character. Finn also went through a lot in this film, becoming friends with the new character Rose, who is a little under developed, but overall a great addition to the cast. Then there is Rey, who we already knew the best from the first film, and is still in the main character roll. She doesn't get as much fleshing out as the rest of the characters, which is fine considering she had the most in the previous film. Lastly there is Kylo Ren who was even better in this film than in the last, showing us some more of his origin story and how he became the villain, which we really needed to see for his character progression through the series.
The plot structure of this movie, without going into spoilers, takes place in three different places at once. Firstly you have Rey and Luke on the island, then you have Finn and Rose, who go off to another planet to find someone who's help they need (this isn't a spoiler by the way) and then you have Poe and Leia on the rebels' command ship. This film juggles these plot threads rather well with some feeling a little less important cough cough Finn and Rose cough cough. But overall this film does a really good job with its cast and making them all feel "important" to the plot.
There are way more action scenes in this movie than any of the originals, and probably the best scenes in the whole series. They have the right balance between the acrobatic fights from the prequels, and the more methodical fights from the originals, making for some epic scenes.
This is probably the most emotional episode because of the shift in theme, making it feel more tense than in the original films. For example, in the original movies you had the rebellion who were the underdogs, but you never really feared they would lose. Whereas in this film the rebels are closer to defeat than they have ever been, on screen anyway. You see deeper into the lives of the average rebel, making deaths feel a little more painful than just another pretty explosion, which I believe Rogue One tried to do, but because we already knew the outcome of that film we didn't get the full effect.
This movie is the least "Star Wars-y" Star Wars movie of the series. Some scenes almost feel out of place in Star Wars specifically the casino that Finn and Rose visit. It feels to familiar, almost like a casino from Las Vegas, but at the same time it takes us to places and settings that we had never seen, so overall it's a positive.
Okay, from here on out I will be expressing my biggest complaints. But know that, while they hurt the movie, the movie is so good in other places that it makes up for its shortcomings.
Firstly, on the bad end, this movie made several massive plot holes in the previous movies that desperately need an explanation. Another complaint is that this movie introduces several new interesting characters that don't get fleshed out, which is a shame.
This movie takes several risks. While some pay off in a big way, some fall flat. I can't say much about this subject, but know that there are a few things that will disappoint you as a Star Wars fan.
There was one specific scene at the end that I felt could have been done slightly differently to make it better, though the scene was one of the best in the film.
On first viewing this, it is probably one of my personal favorite Star Wars films, with a different theme and some great well-acted characters. This movie overcomes any flaws that I see in it.