We visited Disney Quest on our most recent WDW trip, and really enjoyed it.
It has a lot of games (most are free, but there are the occassional games that require an additional fee not covered by admission) and even a nice little internat cafe. The food options are great as well.
We chose to go on a rainy day, when it wasn't the best weather to trudge through the theme parks and had a nice time.
The admission price is a bit steep in my opinion, but if you spend the day, you will surely get our money's worth.
Transportation to and from Disney Quest from Disney resorts is very convenient.