In my opinion, Firefox has never been particularly good. I tried it when it first came out - it was slow and a memory hog. Using IE6 was a much better experience, so I stayed there. It was only once Chrome came out that we had an actual good alternative to IE, and I switched immediately once I tried it.

I would love for Firefox to be awesome, but ultimately (in my subjective opinion of course) it just kind of sucks and always has.