Are both playing near you?
I didn't see the 100 years of Magic show, but here's the rundown on
Disneyland Adventure:
The Incredibles are taking a Disneyland vacation, hoping desperately to pass as an "ordainary" family while there. Unfortunately, the bad guy from The Incredibles (I want to say "Synergy" but I think it's wrong. forgive me; it's 5:37 am) has created a robot. (Remember,the original died at the end of the movie.) He kidnaps Mickey and Minnie and want to change Disneyland into the Unhappiest place on earth.
The Incredibles, with some help from Frozone and their Costume lady, suit up and search Disneyland for their foe. In doing so, they go through some rides-- Pirates of the Carribean, Small World, Teacups, Haunted Mansion and probably one or two more. At the end, of course, good triumphs over evil.
My kids enjoyed it, having been to Disneyworld last summer and being familiar with the rides.
But if your young kids would panic at the sight of Mickey and Minnie behind bars, perhaps the other show is a better alternative??