Being a big fan of the toys, cartoon and comics as a kid (it was called Action Force and Action Man in the UK) I was interested in seeing how Stephen Sommers would adapt it into a live-action big screen movie. And although it was 90% CGI for a majority of the film, the plot was paper-thin, the acting wasn't great, the action was completely unbelievable and over the top and it was generally pretty brainless, I found it to be incredibly fun and very entertaining. As long as you don't take this film seriously at all - it is just a movie for big kids at the end of the day - and you enjoy action films then you should like this, especially if like myself you grew up with it all. The CGI was very top-end quality with some of the most visually stunning special effects I have seen, particularly the whole section in Paris. The action was literally non-stop from the opening scene and doesn't slow down for a second. The characters are all great and stay true to their cartoon and comic book forms, but there are plenty not used in this so I can see a whole bunch of sequels on the horizon.
Overall this probably won't be everyone's cup of tea but for me, I enjoyed it for what it was and will definitely be getting it on Blu Ray when it's released later in the year. If you enjoy films like XXX and TRANSFORMERS then you'll most probably like GI JOE too.