Lots of the mature content from the book is toned down considerably, and I will take my 9 and 12yo to see it, no problem. There is some bad language, but nothing worse than any of the other comic book based action movies of the day.
I liked it, but the 80s nostalgia that was front and center in the book (including the classic arcade games) is really not an emphasis in the movie.
I guess if you were hoping that the prices of your Joust, Pac Man, and Tempest machines were going to sky rocket after the movie, you'll be dissappointed.