I tried Firefox 0.92 and ran into two issues that put me back to IE, albeit probably temporarily. First, when I try to right-click and save something, it doesn't let me choose where to save it. I want that "save as" dialog.
Second, I seemed to run into a memory leak of some kind. After browsing for a while, I didn't have enough memory to open a video... or a document... or even a file.
Now that 0.93 has been released, I may try it again.