The problem with the Avengers movies is that there's just too much going on with trying to give time to all the characters.
This is the best of the three, but I don't think that's saying a whole lot. The first one wasn't very good and the second was worst.
It mostly felt like 2 1/2 hours of cutting from battle scene to battle scene with little in the way of compelling story holding it all together.
I'd say it was "mildly entertaining," but mostly I was just sitting there waiting for it to be over so I get could out of there and watch Fedor and Mir.