[cknight]

It's polished, it's sufficiently customisable for my likes, it features folders, it's completely integrated in to the bookmarks system, accessible from sync'd devices, and allows for simple drag-and-drop rearrangements. All without needing an extension of any kind.

Firefox's "top sites with pinning" does only some of this, and is clunky. Every Fx Speed Dial extension I have tried is similarly lacking in some way or another.