I understand it has some similarities, but it's completely different. The opening scene alone shows that it has an entirely different tone. Sure it has a lot of lighter moments, but the darker ones really surprised me. If anything, I'd say it's similar to Empire in that regard. Kylo Ren also makes the movie much different. Kylo Ren is an interesting character, and he's still young. We haven't really seen a sith like this before, unless you count Anakin in Episode 3, but he's that way for like half an hour and his conflict is extremely rushed. I never truly believed that Anakin would turn, (the Clone Wars made me but that wasn't the movies.) With Kylo Ren, I truly believed this was a man who had an inner conflict. Do we know why he turned yet? No. Obviously that will be explored later. The scene where he kills Han Solo really sold me on his character. He's a man who truly believes that he needs to turn to the dark side, but he can't because something is stopping him. Killing his father erases his doubts. I might get a ton of hate for this, but if you compare Kylo Ren in this movie vs Darth Vader in A New Hope, Kylo Ren is leagues above. Sure, Vader was cooler, but that's not what makes a great villain.
I also believe that Finn and Rey make the movie much different as well. Rey is similar to Luke in terms of her origin, but her character is different. She's someone stuck in the past, longing for something that she would never truly get if she stayed on Jakku. Luke had his uncle. What did Rey have? She's surviving by selling ship parts. My favorite part about her character is that she is amazed by what the world has to offer. Her line about not knowing about the green in the galaxy really sold me on that, as well as Daisy Ridley's performance in general. It should be obvious why Finn makes the movie unique. We've never seen a stormtrooper doubt what he's doing. He's an entirely new character. I can't argue that Poe is very similar to Solo, but there's enough things to him that I love him as his own character as well.
Finally, the plot. Sure, a droid gets stuck on a desert planet with plans/map, and meets the main character, which drags them into the fight against the empire/first order, where they meet an old character who mentors them and then they die. Also there's a giant space ball that destroys planets. Yeah, they sound very similar. However, the way they are executed is very different. The Tatooine Jakku thing isn't that big of a deal. It wouldn't make sense to have a scavenger come from anywhere but a desert planet. The scene that follows is different than anything done in any star wars movie. The scenes with Han and them fighting the 2 gangs is a completely new thing. We'd heard that Han and Chewie were smugglers, but we never actually*saw*them do it. I hope the Han Solo anthology film has a lot of that. The death of Han Solo is different from Obi Wan's in many ways. First of all, Solo's had much more of an impact. We've seen him for 3 movies, and his death is a huge gut punch. Second, Kylo Ren doing it adds more emotional impact as well. Even if he's part of the sith, watching a man kill his own father is much more emotional than an old friend doing it. Who knows, if the prequels were done better, maybe Obi Wan's death would have had more of an impact. Even the Starkiller base is different due to the fact that it's weak spot is actually super hard to damage, but I won't argue that it isn't pretty much the same. The way the movies end are different too. TFA ends in a less happy way. Sure they celebrate, but Ben Solo and Han Solo had just died. (I consider Ben killing Han to be Ben's death, and Kylo Ren takes over, if that makes any sense.) All in all, I think that I can safely say that TFA is it's own movie, and it's a damn good one at that.
Tl, Dr:
The characters of Rey, Finn, and Kylo Ren make TFA a much different movie, and the similarities that the movies share don't hurt the film.