I'd recommend you include it in your pass if it's not too late. DisneyQuest is a great time killer - we spent a lot more time in there than we thought we would. Whether it's a quick half and hour after parks, or waiting for a dinner reservation, or pre-night out or whatever, there's plenty in there to entertain yourselves with. Everything inside is free play and we spent a lot of time on the basketball machines and air hockey. The 8-way Daytona is always great (normally has a little bit of a wait for it too, which says something about how classic Daytona is!).
As for the bigger stuff, you might find it hit and miss, but it's mostly interesting. The coaster simulators as mentioned is great fun if you like that kind of thing and out of all the VR stuff I enjoyed the lightsabre deathmatch thing the most.
They do character workshop things where you sit on a digital easel thing and you're taken step by step on how to draw various Disney characters. For someone with no artistic skill at all such as myself, I highly appreciated that!
They do rotate in some modern arcade stuff, but that's a small proportion of everything else in there. Basically, if you're every stuck for an idea of something to do (difficult in Orlando) or you have a small window of time to kill - disneyQuest is ideal.