It's not bad, and parts are even very good, like the interactions within the team and most of the new characters. I really like Quicksilver, Scarlett Witch and especially Andy Serkis who is not only stealing Wakandan vibranium, but also every scene he's in!
However. The plot feel old and slow and too similar to the first one to feel interesting.
Would this have been the first Avengers that came out I'm sure the tone would've been different, but now it feels like they're phoning it in.