I find the current Firefox to be equal to Chrome in terms of speed, it uses less memory than Chrome, it has much better extensions (including adblock, noscript and vimperator, which are all nicer than their Chrome equivalents), the UI itself is also more configurable (e.g. toolbars, add-on bar; also, we can't even have a bookmarks sidebar in Chrome! In general, if I don't like some aspect of Firefox I can change it, whereas this is not always the case with Chrome), and I like to keep my data to myself as far as possible.

For me, the best thing about Chrome is that it's arrival on the browser scene motivated Mozilla to redouble their efforts, especially in terms of performance and stability, and this has borne fruits with recent iterations of Firefox.