This was one of the better super hero movies I have seen, beaten only by the first, second and fifth Batman movies. Though the second half, especially the final showdown, was somewhat weak. In fact, everything other than Robert Downey Jr. or (suprisingly) Gwyneth Paltrow was somewhat weak.
It is a big, stupid summer blockbuster, it doesn't try to be anything more, and it isn't advertised anything more, but the reviews promised me at least a bit more than that, which left me slightly disappointed.
So it's decent entertainment, but certainly nothing you absolutely have to see. (Unlike, say, "Kirschblüten - Hanami", which probably won't make it out of Germany)