How applications behave with Matrox Dualhead2go?

Matrox Dualhead2go makes it possible to have 2 external screens for a Macbook Pro. It performs that by splitting a very large screen in two smaller screens.

I am very worried as to how will the applications behave with that:

• will the dock be displayed in the center? (i.e. between the 2 screens)
• will all modal dialogs be centered also?
• Are Expose and Spaces working good? Isn't their display broken?
• Is watching a video full screen on one display possible? (VLC, youtube, DVD...)
• Will fullscreen apps work? (aperture for example)
• Is that possible to maximize a window on one display easily?

Note: I have tested an external USB graphic card as an alternative solution, it is way to laggy to be used IMO.

I have this product. All your concerns are valid. Modal dialogs and prompts are split by the program's bezel. The dock can be positioned across only one monitor, but that is the only configuration option. Fullscreen video on one monitor is not possible. Fullscreen apps span both screens, which doesn't work well. Calendar is OK. Mail is impossible, especially when composing a message. It is easy to maximize to just one window using built in hotkeys. However "true" fullscreen is usually complicated by monitor bezels.