Spoilers: (Highlight to reveal)
The Avengers 2 will feature three different versions of Ultron. He starts off very basic but upgrades. It's said he is coated in the fictional metal Vibranium and spends the rest of the film seeking out more. It's also stated that James Spader will be doing motion-capture work for Ultron; so it's speculated that a version of Ultron we could see might be less of a robot. It should also probably be noted that The Avengers 2 shot in South Africa, and Vibranium is found in the fictional African nation of Wakanda, home of the Black Panther.

It's stated that Tony Stark is completely funding The Avengers as there is no more S.H.I.E.L.D. following the events that went down in Captain America 2. The Avengers are now housed in Stark Tower, which has become Avengers tower. Stark has funded new costumes, tech and a new quinjet.

It's said we'll see more of the Iron Legion that was shown at the end of Iron Man 3. Tony has created more Iron Man robots, stated to be like drones, to help keep the peace. Also, the Avengers have a very high public profile in the wake of the collapse of S.H.I.E.L.D.

Regarding the Vision, played by Paul Bettany, it's said the movie costume will resemble somewhat the comic costume (green and yellow), and that the Vision will make his reveal toward the end of the movie.

Some info on the Avengers duds and weapons: They will all have an Avengers logo; Black Widow will be using two fighting sticks that can stun; Hawkeye has a new costume (as seen in set pics); Hulk has stretchy pants that can now grow and shrink with transformations; War Machine is said to have a cameo, with Falcon also a possibility.