DH and I just went to DisneyQuest for the first time (only because we got the free ticket upgrade w/ our package) and while we thought it was fun, we would never actually pay to go there. Our kids are 5 and 3 (were with my parents that day) and would have been too short for most of the fun attractions and not very interested in the rest.
The place was practically empty when we went at opening on a Wednesday in January and we zipped through all the featured attractions and played lots of 80s video games in under 2 hours. We especially enjoyed Pirates and Buzz. I lived out my 80s childhood dream of unlimited games of Ms. PacMan, Centipede, Donkey Kong, Dig Dug and Burger Time.
I'd definitely check height requirements because your kids will be bummed if they can't do most of the fun feature stuff. However, if they love arcade games, it's pretty cool to just walk up and push the start button. They also had stuff like the basketball games, etc.