Yeah finally some real stakes in a superhero film. Didn't you find that refreshing?
Okay so here's why I enjoyed it..
1) It was very well thought out. They've been teasing Thanos since Avengers 1, and a lot of the MCU films have been related to the Infinity Stones in some way without making it clear that it was tied into a single storyline until Infinity War. It also built on the dynamics from Civil War. It's the first time that it actually felt like all these movies were operating in a single universe with a coherent story.
2) There were some heavy feels, especially with the Gamora plot. Thanos sacrificing her, then Star-Lord losing the plot and screwing up the whole battle because of his grief. And Tony Stark's bit at the end, Loki's death (which feels like it will be permanent). Vision's death... some great moments in there.
On the bad side it went on too long and there was too much information to digest and too many side-stories.