Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Firefox 1.5 has been out since November 29, 2005, and has garnered glowing reviews around the Internet. This is not one of them. In fact, I recommend holding off, at least temporarily, on installing Firefox 1.5. I've installed and used Firefox 1.5 through the betas, and had no trouble, but somewhere early in the Release Candidates I began to encounter problems. And I'm beginning to learn that I might not be alone in that. I can't speak with authority that a large number of Firefox users are having issues with Firefox 1.5; I am, though, hearing sufficient reports about trouble to be cautious.
The issues people are reporting to me are highly varied. Some of the more dramatic problems have included damaged Firefox profiles and loss of right-button context menus, but the more common issues by far have to do with CPU and/or memory usage.