I went to Disney Quest in 2007 and again in 2010. It was included with the ticket package we had so it was not an extra cost. We were there so we went in.
We were all adults in our party and no kids. It seemed geared to kids so they may like it more. All in all, I was not impressed with the attractions and did not think it was that great. I would not go again. But, then again, if you have never done it before then it may be good just to have experienced it once.