Let's get this out of the way at the start. Wonder Woman is a really, really good superhero film. When grading on a curve against the other entries in DC's Extended Universe (which includes Suicide Squad, Man of Steel, and Batman v. Superman), this will likely feel like one of the best films ever made, but then that doesn't set a very high bar. If we compare it to the nearly 30 other live-action films based on DC comic characters since the '66 Batman, it's easily in the top 6.
Wonder Woman has had the deck heavily stacked against it from the outset. Coming on the heels of three extremely poor prior DC films, Warner Bros. needed a win to keep their hopes of their wider franchise efforts alive. There have been the very vocal elements of the anti-women groups charging that women-led films will somehow lead to the downfall of western civilizations. A director that was a relative unknown quantity, with only one prior feature film credit (granted, it was for the award winning film Monster, but that was a crime drama, and Wonder Woman is a superhero action film).
Warner Bros. has had a terrible track record of second guessing their film's creative teams. They are so hung up with watching what's working in superhero films from other studios that they have often called back for recuts and reshoots, and those desperate moves hadn't yet wound up doing anything but dragging their franchise down to the point where it's head has been barely above water. This time they [largely] left director Patty Jenkins and the writing team of Allan Heinberg, Zack Snyder, and Jason Fuchs alone.
The result is a film that while not perfect (I'll get to some points shortly), it's a lot of fun. The story is relatively solid, the action sequences are well executed, the casting works wonderfully for the characters (with a particular nod both to the lead Gal Gadot and star Chris Pine).
The film opens with the backstory of the Amazons and their hidden island of Themyscira. A war had raged between Zeus and the god of war, Ares. To help defend mankind of Ares, Zeus created the Amazons. With Ares defeated, the Amazons remained on their island and waited for the day that he would rise again to threaten the world. We follow the young Diana / Wonder Woman through her combat training (against the wishes of her overly-protective mother, the Queen of the Amazons), as she grows. It's like the coming of age sequence in Moana, just this time with swords, spears, and bows. In the midst of their relatively tranquil world, a damaged airplane crashes within the area of the island's bay and Diana rescues the pilot. It turns out that the pilot is Steve Trevor (Pine), a British Spy during the late period of World War I. When he tells Diana about the war raging in the outside world she decides that it must be Ares that is behind it. She decides to help Steve escape the island so that she can hunt down the god and put an end to the war.
There's a handful of fun fish out of water scenes with a naive Diana experiencing the outside world for the first time – including dealing with her finding more appropriate clothes to wear about London than her traditional armor. While those are some of the laughs in the film, they also include some of the more disappointing lines. When Trevor puts glasses on Diana, his secretary Etta Candy (played Lucy Davis) comments "why do you put glasses on the most beautiful woman in London" – thus implying that glasses by definition reduce the beauty of anyone who wears them (and especially women). And in a second point, when Diana is asking about a corset and what it's for, Etta says it's to "keep your stomach in." Diana asks "why would you want to keep your stomach in?" To which Etta replies with, "that's something only said by someone who doesn't have a stomach to keep in." In both cases, they're odd detractions in an overall film that celebrates the strength of women.
The other strange leap of logic is that when they leave the island, Trevor and Diana go to sleep, and when Diana wakes, they're sailing down the Thames. That their small craft made it from anywhere to London in a single evening is just rather jarring.
However, other than those points, the film as a comic-based property is a great roller coaster ride. Watching the mothers and daughters who were in the audience cheering on Wonder Woman, it makes me happy to know that Hollywood has finally gotten around to giving a film like this a chance, but then I feel a bit sad that it's taken this long to get here.
Another plus for this film is that it entirely does not suffer if someone watching it isn't familiar with the comic source material. In the Batman and Superman films, it's mostly an all-encompassing in-joke, where in this film, if you know the comics you will recognize various name drops, but beyond that, the story is all here, self-contained.
Note that Wonder Woman does NOT have any mid or after-credit scenes. So once the credits roll, you can head on out.