I thought the first one, Rise of Cobra, wasn't bad. The exoskeleton suits were a bit much but overall it wasn't a bad 'popcorn' movie.
Unfortunately I was totally put off by the second movie, Retaliation, where they wiped out all of the major characters except for a Roadblock, Flint, and Lady Jaye! COBRA wasn't spared either with Zartan and Firefly both getting killed off as well. To kill off characters like Duke and Scarlett may have been a way of doing a reboot from the first movie but it made no sense to kill off all of the major GI Joe characters like Duke and Scarlett that were such major parts of the original animated series.