We did this a few weeks ago and enjoyed it very much. It was a crystal clear day and we could see for miles. You could see the major landmarks from all the parks except MK - the castle is hidden behind the Contemporary. We could see well into downtown Orlando and beyond too. You get a fantastic bird's eye view of all of DTD and the neighboring resorts (Saratoga Springs is HUGE!)
Our captain was very nice, and he went around and for anyone that brought a camera, took our photos.
The ride itself was pretty smooth. There were a couple of small "bumps" on the way up as they release the brakes. Coming down was super smooth, although you get wiggled around a bit as they roll the balloon back into landing position on the platform.
There was just the slightest of breezes on the ground, which translated to a bit more up in the air. However they loaded fewer people on board, so we were still able to go up the full 400'.
You definitely need your sea legs, and if you get motion sick, try not looking down (worked for me). If you're at all afraid of heights I'd skip this one.
Some pics...
Here are some pics from our flight...
Contemporary in the distance. You can't see the castle because it is behind it...
Epcot...
Saratoga Springs...
One last tidbit we were told when we bought our tix. If you save your receipt, you can come back at any time, and as long as the receipt is still readable, you'll get 20% off your next flight.