Captain America: Civil War May change after I’ve seen it again, but for now it narrowly takes the top spot. A
CA: The Winter Soldier A
The Avengers A
CA: The First Avenger Marvel’s most underrated IMO, but I’m a sucker for the period setting. A-
Guardians of the Galaxy Nearly perfect until the somewhat underwhelming climax. B+
Iron Man Similar to Guardians, has an underwhelming climax. B+
Avengers: Age of Ultron Has trouble balancing characters and has too much sequel setup. B
Ant-Man Pretty generic. If it weren’t for Rudd and the scenes where his friend is explaining stories B-
Iron Man 3 Pretty good until the Mandarin twist. Everything after that is trash. C+
IM2 There’s some good stuff in here. Sadly, it’s hidden behind pointless scenes and sequel setup. C
Thor Pretty bland other than Loki. Thor’s scientist friends’ intern is incredibly annoying, Thor is suddenly worthy despite not actually changing at all. C-
Thor: The Dark World Literally the only good thing about this is Loki. D+

My ratings of each movie actually tend to slightly shift in my head sometimes.

Never watched Incredible Hulk all the way.