Go get your copy, Firefox 3.5 is out. 
And if you have a couple extra minutes have a quick view of Mike Beltzner’s preview of what’s new and exciting in Firefox 3.5.
First noticeable difference for me has been its speed. It rocks — blazing fast.
The bag of goodies for Web Developers is surely going to take Firefox 3.5 another leap into the future. However, to be fair to Safari I must point out that Safari had passed Acid Test 2 ages back. Its good to see GrApple Yummy(theme for Firefox that makes it look like Safari) working on the new release of Firefox 3.5. Go get your copy!
I am using it and loving it…
The latest version of Mozilla Firefox is, exactly like you said, blazing fast. And it is actually using less memory now as well. Private Browsing is another great new feature that is likely to become quite popular.
The one and only annoying thing so far is Firfox 3.5 doesn’t seem to honour colour profiles. Hopefully Sean will come out with the add-on soon. As the articles states:
Color correction can be controlled by setting the value of the gfx.color_management.mode preference, as mentioned above. And here is another one that throws some light on the process.