With the announcement of the next alpha-level release of Firefox 3, I went ahead and installed it on one of my Linux boxes to give it a quick test. As I run the stock Mozilla versions of the apps, rather than the versions from the Linux distro’s repositories, and use update-alternatives to point to the versions I want use, installing it alongside my stock 126.96.36.199 was quick and easy.
The bottom line: generally positive. Much of the work so far on this new version still remains behind the scenes, but some of the underlying work on the interface is starting to show through. I noticed, for instance, that it seems to be paying attention to the theme I have installed on my GNOME desktop in how it renders form controls like checkboxes, radio buttons, and buttons — in some cases (but to be honest, I haven’t looked at where, because it’s clearly not everywhere — maybe only where the Web app/site in question is not providing any styling on the controls?). There are some (mostly) subtle changes in the appearance of some pages that I visit often enough to make them noticeable (e.g., Google’s Gmail and Reader apps). So far, I haven’t found anything that feels like a show-stopper, and all of the plugins I normally use seem to work OK.
I do have a big caveat to throw on this, however: I don’t have any browser extensions installed on my normal Firefox installation, so I can’t really indicate whether there are significant incompatibilities that might get me there. More to come as I try this on a couple of other systems.