Ragnarok was very different from the other two Thor movies. It is much more of a comedy, the tone is half guardians of the galaxy and half Flash Gordon. However it does not fall into the trap of hurting its own plot for the sake of laughs, the threats feel real.
The thing that struck me is how much it shows the short comings of Thor. He really is not someone who should be on his own, while a good man he is still arrogant and overconfident, and does not think as deeply or as often as he should. That is one way in which he and Loki make a good team, between the two of them they make one functional person.
Speaking of Loki, as always any scene with both of them is worth its weight in gold.
While I would not say it’s the best Marvel movie, I would say it’s the most fun and the most funny.