If Your IQ Is Above Average, You Will See This Film as Superior To First Avengers

Rating: 9/10 (3 May 2015)

Also, if you have attention deficit disorder, you will like the first Avengers better. However, if you like a deeper and darker story line, and you do not have an attention deficit disorder and have an above average IQ, you will like this film.. Here are the reasons;
1. Better character fleshing - In the fist Avengers, we had characters come together to stop a basically mindless plot by Loki to rule The Earth. Character motivations had little to no fleshing. Here, we have each character's motivation as an Avenger delved into much deeper, and in a much more realistic and human way. (I.E, Banner and Romanov motivation and interaction here, it does make a ton of sense and it's not forced if you understand the character motivation)
2. Better antagonist motivation -- Ultron's motives make sense. In some ways it's not hard to actually agree with his agenda, which makes him a much better and threatening antagonist than Loki, who I found to be a sniveling childish punk in the first film. Ultron has a mission, and as artificial intelligence his point of view is to evolve beyond that of a simple program, and has the freedom to interpret what it means to "bring peace." I really liked this angle much better than Loki and his boorish childish ego. In fact, Ultron reminded me very much of the Agent Smith character from The Matrix trilogy; very similar point of view and mindset which to me makes Ultron far more menacing and interesting - it's not a stretch to actually see his point of view and actually agree with it in many ways.
3. Better/deeper dialog -- Do not believe other reviewers when they harp on the cheesy one-liners. They fit in decently here, not out of place like in the last Transformers film for an example. Occasionally, a few do seem forced, but in no way do they subtract from the much more tied-in and serious undertone this film has over its predecessor. Additionally, this film fleshes out Tony Stark in a way only the first Iron Man was able to accomplish. One weakness I did find was the Steve Rogers character taking a small step backwards in this regard. However, Banner, Romanov, Hawkeye and Stark characterizations move forward while Thor remains consistent.
A great new addition is "The Vision" (Thor's Vision) who is basically AI come into genetic life, and is a cross between Jarvis and Ultron. (The Vision is "worthy!") The end of the film fleshes him out properly where he converses with Ultron and points out the differences between the 2 AI's.
Now, if you want mindless action, which is how I saw the first Avengers as; the kind of mindlessness that does not require you to actually pay attention and enjoy the greater overall depth here, you probably will not like this film, and may even find yourself confused by it. This seems to me to be the tone of the negative reviews for this title.
In my view, this film ties up and transitions the Marvel Universe in a most efficient way, (except for the single mid-credit appearance, which is basically a do-over) which should make the next chapter, "Captain America, Civil War" (Ant-man is a separate slice of pie for now) a smooth transition. Note that the first Avengers film did not do that (Thanos end credit, poor continuity into Thor-Dark World.)
Conclusion - If you like a deeper story line with an antagonist who is similar to The Matrix's Agent Smith, (this film has a bit of a Matrix feel) and like your brain fed along with top-notch action, This Avengers film will be a far better experience for you than the first one. However, if you like your Marvel action spoon-fed with little to no thinking required, you may not like this one and certainly will not like it better than the first Avengers - you may even give it a negative review.