We were sold on the Keyport Slide when it promised not only to banish key-based clutter, but also incorporated two of our favorite things: flash storage and a beer access device.
Since you need to have the D415 open to do anything, the clear key would be more convenient on the slide out keypad where you will use it to erase mistakes.
The most effective way to use notes is to use a series of one, two or three word phrases that will remind you of your key messages and points for each PowerPoint slide.
The results are stunning, although I think there are some important caveats. (I detailed both here.) But the key data, and the thing that really impressed me, was this slide.