Upon first glance, I've got a handful of UI complaints. Things that could obviously and easily be improved, I think.
- The "Title Button". Why orange? Why so prominent? Why so high-contrast?
- Clicking The "Title Button". Ohh my. This is a UI abomination. OK, maybe it's not that bad, but it's really bad. The groupings are unclear. Why two columns? What is the difference between items in the left column and the right column? "New Tab" has an arrow indicating that mousing-over it will reveal more stuff...or, is it pointing to the right column? Edit is italicized for fun! The Cut icon (scissors) has to be the worst Cut icon I've ever seen. Almost doesn't look like scissors! The Print icon...
- The Tabs. I see now that Chrome has spoiled me with a really nice tab design. These Firefox 4 tabs are so blocky. The vertical lines separating the tabs are too bold. The fact that both sides of each tab intersect with the horizontal line beneath them is too harsh. Chrome, by contrast, has a neat curved tab design, where only one side of the tab (except for the leftmost tab) intersects with the line.
Chrome Tabs: Nice
Firefox 4 Tabs: Ugly
Microsoft Word's tab design, for instance, shows an interesting way to improve upon Firefox 4: by hiding the border of the not-in-focus tabs. I guess this might not work well in Firefox, given the design of the Bookmarks bar.
- The Buttons and General "3d-ness". The Home Button. The Bookmarks Button. The Firebug button (if you use this addon). They're light up-top, dark towards bottom. Have a slight shadow. Rounded corners. They look nice, but these details just aren't necessary. Too many lines. Accentuates the whitespace (the area in between buttons) too much. Again, see Chrome for contrast (apparently even the Chrome logo is going flat)
Aza, where were you!?