All of the people complaining about lack of depth or it won't be much or this or that... well get over it. Who the **** cares about that? This is going to be an epic mix of superhero mish mash doing whatever it takes to save the earth and the 9 year old in me says it will probably be the coolest film I'm ever going to see. And that is all that matters because that is what it is meant to be.
If you want story and depth, go watch the TDKR, but if you want to just to cheer on a group of fictional characters to avenge the earth, then this is defo the film you should watch.
All I remember when I watched the TDR was I sort of liked it, but at the end of it, I went back to watching Iron Man for the hundreth time just because it was much much cooler than TDR despite being a lesser of a film.