The one improvement that I liked in MetalScroll is that I can split the code window by dragging the top right corner. This Visual Studio feature was hidden earlier by RockScroll.
MetalScroll has changed the keybinding required to highlight words to Alt+double-click. I prefer directly double-clicking and thankfully this can be changed back.
MetalScroll also offers settings to change the colors and dimensions, all of these can be accessed by double-clicking the scrollbar.
To change the color of the highlighted word, go to Tools → Options → Fonts and Colors. Here choose MetalScroll in the Display items section.
Sadly, MetalScroll works only with Visual Studio 2008 and 2005. It would have been great if it worked with Visual Studio 2010.