The Multimedia Dock is overpriced, but I bought one, and I like it. It works pretty well, but insertion and removal are more difficult than they should be. I like having the clock and alarm function, and the low intensity mode allows my wife to sleep. I don't quite get the appearance of the low light mode - it has a cloudy glow across the entire screen that looks almost foggy, but maybe that is unavoidable.
One oddity I have found is that the magnet in the dock can impede screen rotation at distances up to 2-3 feet away, with certain relative positions between them. One of those positions just happens to be mine when I am trying to browse or read a Kindle book in bed (yes, the DX is perpendicular to the ground). To get it to change its screen orientation between portrait and landscape, I usually have to rotate around the axis of the DX momentarily to make its body perpendicular to the dock.