I thought parts of it were really great. The ScreenSlaver's monologue and subsequent fight against Elastigirl were really cool. As always, the family stuff is the best — I especially loved getting some interaction between Violet and Bob, since they didn't get much in the first one. The action scenes were great too.
Other aspects were disappointing though. I didn't really mind the plot, but I didn't like how the characters felt like they didn't progress much/didn't have as much to do. Like this was supposed to be Elastigirl's movie, but it doesn't feel like she's changed much by the end (as opposed to Mr. Incredible's arc in the last one, which was really well done).
Mr. Incredible's arc in this feels like it never goes anywhere (his jealousy towards his wife's superhero success just kind of goes away). Violet gets to do more, but what she goes through here feels too similar to the last one (wanting to be normal, hating how her powers affect her personal life, but accepting it by the end). Poor Dash had nothing to do in this one. And JackJack is fun but the antics with his powers got old after a while.
It was a fun movie, but definitely not on par with Incredibles 1 (which is my favorite Pixar film).