I have used Opera for several years, I will swop to Firefox sometime, but not yet. As you said Firefox now nearly has all the features of Opera, which Opera has had for years. As the saying goes if it aint broke don't fix it. I used to use IE for CP, I now use Firefox, only rarely do I find a site that Firefox won't render. I remmeber the days of incompatible PCs, the net is great as it is 'standard' it would be nice if websites were not designed for a single browser, I am not knocking CP about this. Perhaps when/if Firefox gets to 50% that may happen, but I am sure the bean counters will try and prevent that!
"Nothing is impossible for the man who doesn't have to do it himself." - A. H. Weiler