If you try to adjust color: Grayscale values will not work, use crayons, color wheel, or else.
The "Speed" slider appears reversed; may be, it's just me.
The preview window of the Pref. Pane doesn't reflect recent changes, unless you close Sys. Prefs, or switch to another pane, and back.
The font defaults to Helvetica regardless of the previous selection, when open font customization box; it will, however, take new selection, but you have to scroll there.
The movement of the clock on the screen is somewhat hectic, but it may be a matter of taste.
Overall: useful saver, tiny file size, cheap, but needs some refinement :)