The Avengers: Age of Ultron was a great sequel to its predecessor. I've seen it twice now, and I liked it better the second time around. It had everything I wanted from it: action, drama, the works.
One thing I do have to say though, the Avengers didn't lose anything meaningful by the end of the film. Sure, Quicksilver died to protect Hawkeye and a helpless kid, but that barely meant anything to us, the audience. Quicksilver was a newcomer, and I didn't have much time to get emotionally attached to him before he was taken from us. The trailers for this movie gave me the feeling of dread. Someone was going to die and something really bad was going to happen. Not much happened, and Ultron didn't really accomplish anything.
The movie did a great job of sewing the seeds for Captain America: Civil War, but failed at making the characters lose something. A good story always needs to push characters through situations of loss and epic failure, but Avengers just didn't get it done.
Besides these thoughts of mine, the movie was spectacular, and was a great continuation of the MCU.