Just got back from seeing the movie. Spoilers ahead, but to put things in brief: go see it--NOW.
This may be the best Spider-Man (and, dare I say, Marvel) movie ever. It has the perfect balance or humor, action, and intensity. Tom Holland nails every aspect of the character, and--more generally--the complex emotions of a teenager. He makes me believe he's Spider-Man, in a way I never really thought anyone could.
Michael Keaton is phenomenal as the Vulture. He makes a really compelling and interesting villain, and fluctuates between awesome and terrifying. If you don't want huge spoilers, STOP HERE...
The revelation that Vulture is Liz's dad was perfectly executed. I had read a rumor about it months ago, but forgot it, so the surprise was utterly out of left field. The tone of the movie does a complete flip when this is revealed, and it is glorious. The scene between Peter and Toomes in the car is an incredibly tense, really well done bit of filmmaking, and it had me on the edge of my seat.
The emotional conflict in the movie is great as well. The scene of Peter trapped beneath the rubble almost broke me, because I truly believed his terror and fear, and it felt exactly like how a child--even one with super powers--would react in such a deadly situation. It only made it more powerful when he summoned the will to extricate himself and continue fighting.
The use of Tony Stark is sparing, but effective. He gave off a great mentor vibe, and his conversation with Peter on the roof after the ferry incident felt very real, and shows how Tony has matured since his first movie. The Gwyneth Paltrow moment at the end was a nice surprise too...
I wasn't as surprised by the reveal that Michelle is MJ. It was well predicted by theorists, and it made sense. We'll see how it develops going forward.
The action and special effects were great, and the movie felt neither too fast or too slow. All of the supporting characters are nicely portrayed, and everything pays off really well in the end.
All I can really say, again, is that you should go see this movie if you're only thinking about it, and definitely see it soon if you wanted to!