This review will contain spoilers!
I saw it at the Alamo Draft House, and they did this cool thing before the previews where the showed clips from the previous movies that included Thor, and giving basic plot summaries. It was useful, because I'd almost completely forgotten what happened in Thor 2: The Dark World. Seriously, of all the MCU movies, I think it's the only one I haven't seen multiple times. Thankfully, even without all that, Ragnarok stands on it's own.
It's also something of a reboot for Thor, who never really seemed to quite fit in with the rest of the Avengers. He was always just sort of there, and part of that is the fact that even among Iron Man and Captain America, Thor is... well, a god from a magical realm... Kind of at odds with everything else, up till Doctor Strange anyway. There's just something a little goofy about Thor, his hammer, the rainbow bridge, etc that doesn't fit in with the aesthetic of The Winter Soldier or Ant-Man. In a lot of ways Hulk has the same problem.
On the other hand, that bright Jack Kirby craziness fits right in with the Guardians of the Galaxy, and Ragnarok took not only it's color pallet from that series, but also the goofiness of it all. And it works! It fully embraces the weirdness, and crafts an amazing story out of it.
To offset the goofy is the darker side of the story. Thor and Loki's older sister Hela, as portrayed by Cate Blanchett, was pitch perfect! Her costume, taking it's cues from Loki is form fitting and no nonsense, except for that horned helmet, and looks fantastic as Hela tosses swords in her attempt to take her rightful place (oldest child) on the throne of Asgard. I can't get over how much ass she kicked, and all without one instance where it felt like she was a female villain. Hela was clearly the bad guy first, and a woman second.
Valkyrie, played by Tessa Thompson, was also spectacular at kicking ass and taking names. I really enjoyed her no-nonsense way of handling Thor, Loki, and the Hulk! I hope that she gets a fair amount of screen time going forward. I'll be disappointed if she doesn't show up in Infinity War.
As much as I enjoyed Jeff Goldblum's GrandMaster, Topaz's reactions to Goldblum's acting stole each and every scene they were together in.
And the bit with Doctor Strange, where he was having none of that Asgardian bullshit? Brilliantly done. Can't even imagine his reaction if/when the ship arrives on Earth to set up a new city... Of course with Thanos in the picture, that'll probably be near the bottom of his priority list.
In short, if you liked Guardians of the Galaxy, and thought Thor 2 was forgettable, you'll probably like Ragnarok!