I have just tried the Intel version and I must say it works well. It seems faster than the "ordinary" Firefox and the Aqua elements are a nice touch. (Although not so well integrated as in Camino.)
However, there's one little problem... A few add-ons do not work. The icon of DownloadHelper doesn't even show on the toolbar. I unistalled it and reinstalled it but... no way!
Maybe this Firefox still needs some work to peform without glitches...