Everybody seems to be writing about the new firefoxand as a loyal user, I shouldn’t stay behind. I’ve been using the alpha and beta versions and they have proven to be mostly trouble free (as much as you could expect from alphas and betas).
The alphas were a little unstable and I encountered a couple of crashes (over a period of several weeks). That hasn’t happened to me with the beta which I’ve been using since it was released. The largest problem has been the intially slow pace with which extensions are tested and ported. By now most of the more relevant (and actively maintained) ones have been ported. There are still a few extensions missing. Presumably the developers are waiting for the final release or simply not interested in immediately fixing their extensions.
Now the new features. At a first glance, not much has changed. Most changes are under the hood. The most visible change is no doubt the rearranging of the preferences dialog. IMHO it doesn’t make much difference but I agree it is slightly nicer this way. Also the rss button has relocated from the status bar to the locationdropdown. IMHO this is slightly awkward or at least unconventional. And finally FireFox now has error pages for timeouts and other server errors, just like IE has had for years. Other than that, I can’t think of any relevant, eye catching changes.
The most visible change to end users will be the performance increase. When 1.0 was released last year, it was released off a branch which had been frozen quite some time by then. Meanwhile development on trunk (a.k.a. mozilla 1.8) continued and about 1.5 year of development has accumulated there, most of which will end up in FireFox 1.5. FireFox 1.5 has a new clever mechanism for back and forward which prevents it from rerendering a page and caches the results. Consequently, going back and forth between pages is now fast. Also normal rendering of pages has seen some improvements. It is hard to quantify this but it certainly feels faster.
So to summarize, some minor feature and gui development, lots of under the hood changes which you will notice in the form of snappier performance. Other than that it is still FireFox, a damn good browser, a solid upgrade from any browser you currently use.