So far I found one nice thing about it.
This makes sorting easier, and hides away any NSFW material unless you choose to enter it via Grouping of Tabs as I've done here.
This is a welcome change for me, as I used to run 3-4 Firefox windows in order to sort my tabs.
I did slam Firefox with 400 tabs, something I would have used in the past, and it held up better than usual. Of course with that many tabs the memory has an excuse to be so large.
My grand test was running 5 videos, 3 large downloads and a flash game.
Normally a single video and a download would cause PluginContainer to go apeshit and lock up the browser, but much to my surprise; PluginContainer held up quite strong.
524MB of memory was used, and as each video finished playing, roughly 70MB was freed up instead of remaining idle; closing the video tab altogether cleared 30MB more.
The flash game which used to lag and lockup midway actually completed without a hitch as well.
The 5 videos also didn't lag, which blew my mind.
As a brief test run, I can easily say that FF4 handles memory a lot more efficiently, though I still believe that if you're playing a power intensive game or streaming your desktop, that firefox should still be terminated to free up as much as you can.
I'll continue to test things as time goes by, but so far it exceeded my expectations in terms of handling flash videos/games ect.
The team finally did something right
Give it a try, you may like it.