The startup time and JS speed improvements are noticeable and welcome, and the visual tab previews are finally here and worth the wait.
By default, the new visual tabs are currently hidden in the FF3.6 alpha build, you can easily access them via an about:config tweak. Read on to learn how to add these…
Adding visual tab previews to FireFox 3.6 alpha
To add visual tab previews in FF3.6a. just open a new tab an enter:
about:config. Then, add the values:
browser.ctrlTab.previews = true
browser.ctrlTab.mostRecentlyUsed = true
Now, restart FF3.6, open a couple of tabs and press CTRL+TAB to activate it. This should now show the new visual previews to both new and last used tabs.