Google Chrome has been giving Firefox a run for its money in performance and stability, but Firefox still has a commanding lead in terms of features — especially when you factor in the massive ecosystem of Firefox add-ons. Google is looking to narrow that lead in the near future with the announcement of its extension gallery. The site is only open to developers to upload extensions at the moment, but you can find plenty of unofficial sites and extensions already.
You might notice that the instructions on creating a Chrome instruction seem a lot simpler than creating a Firefox extension. Chrome sticks to technologies that Web developers know, and don’t require learning XUL.