I don't get why everyone hates on Twiz.. its not as IN YOUR FACE as sense and its integration doesn't totally kill the stock android feel.. and what it does replace sucks anyways.. Like im using Eugenes CM7 right now and its great, but certain things are just better in Twiz..
The launcher is debatable.. I use Go personally..
The status bar with toggles was started by Twiz and is now used in almost all custom roms including Cyanogen..
Slide finger on the status bar to change brightness level
A better phone App than stock Android,
A better Contacts App, Slide to call or message..
A Nicer looking Music player..
And other than the bloat like all share and what not it doesn't really change much more...
I use an ASOP ICS build on my Wife's Sensation and the UI is not that much different than Gingerbread. Few new bits here and there.
I guess its a personal choice.. Unlike Sense Twiz doesn't slow down the device..
As for Ginger VS ICS I haven't tested our yet but On the Sensation my Wife seen a major battery life increase and some performance as well so I hope it the same here.. !!!
Google Nexus 4
Team Win Recovery