I thought that Avengers: Age of Ultron was a ridiculously fun movie. There were some parts that fell flat, but the highs were so high and it gelled so strongly in the end that I loved it. I will have to see it again; my theatre was excited enough that I missed some lines due to laughing, cheering, or other boisterous reactions.
The movie opens with the Avengers on a mission to find Loki's scepter. (Those of us watching Agents of S.H.I.E.L.D. could enjoy the tie-in.) I thought the opening looked super fake - maybe it was all that snow? But soon enough Tony Stark was getting excited by a secret entrance and I was absorbed into the movie.
As much happens in Age of Ultron, there is room for a few quieter scenes. I really enjoyed the party, where characters from throughout the franchise (and Stan Lee) came together. Tony and Thor getting into a verbal fight about who has the most impressive girlfriend was ridiculously adorable. I also enjoyed Natasha putting on her best noir dame attitude to romance Bruce Banner. The romance ended up getting short shrift, but I still might have feelings about Natasha and the Hulk, which I did not expect.
I also find myself really liking the new characters, Wanda and Pietro. One of the advantages of Marvel's Avengers was that it didn't have to waste time on character introductions, since they'd all had origins in other films (mostly). But the way the twins came into the Avengers world really worked. I first loved them when they failed at intimidation, and then when they both had cute moments with Hawkeye. And if you were sad Hawkeye barely had anything to do in the first film, you'll be happy with Age of Ultron. He gets the line reading of the movie with one pep talk.
I find the way the Marvel Cinematic Universe is shaped so pleasing. Getting to revisit these characters each year is a treat. Age of Ultron can't please everybody, but it did please me. Bring on Phase III!