For our family adding the entire WP and more option was about the same cost as one day at DisneyQuest. So, of course we went ahead and checked out WP's also.
Anyway, as far as DQ goes, my kids loved it. Of course my two boys are hardcore gamers! My dd found many things that she liked as well though, especially the animation class.
We actually went twice during our trip. We went once as a family, and dh and the boys went back on another day while dd and I shopped at DTD.
We went on weekdays right before lunchtime, and did not find it to be crowded. Also, we had a very nice, quiet lunch there.