Off the top of my head, Live Bookmarks and the Find Toolbar are Firefox-only. There are some extensions that will only work on Firefox and not Mozilla, but there aren't too many of those. Firefox is, at its core, a basic browser. To reduce bloat and system load, you choose which features you want via extensions, and you don't wind up with stuff you never use.
Good deal. I guess the live bookmarks thing is a pretty cool thing.