Well, let's start with the telephoto. This clip is a 2 second Windows Media file:

http://dmzconsulting.net/video/Canon%20Test%203%20Telephoto.wmv

Now that is 2 seconds handheld at max telephoto. The OIS is unbelievable. Handheld at 800mm? Very steady. Probably the most impressive feature.

The next two frames are pictures of the ceiling. Two lights and the ceiling behind them.

http://dmzconsulting.net/video/Canon-XL2-Test-3-Light.png

http://dmzconsulting.net/video/Canon-XL2-Test-3-Light-Enha.jpg

The first is the raw image. In the second I tweaked the the curves to bring out the detail. As you can see there is a lot of detail sitting between 5 and 35 IRE. Black stretch was not turned on. Again, to seemed to show a good range. Also note the clarity around the light.

I didn't have a light meter with me, however it appears to me to have a broad dynamic range.