Well, as I noticed every 4.2.x rom works "like a butter " when I scroll something or during multitasking, but everything what is connected with speed ends here. Newest android is smooth, but very languid(?). You have to wait at least 5 seconds before something will happen. Example: Click on the telephone app, then wait before it will show, and then wait again <longer> before it will load up. Android 4.1 is faster, but still it has no chance with 2.3. Currently (Android 2.3) when i touch something i wait not longer than 1 second, and it shows up.
We didn't metioned android 4.0. (I will skip 3.0 and 3.1 because of... Oh, you know!
). Let's talk about this "wonder of nature"! 4.0 is a great hybrid between speed, functionality and look. ICS works fast, quite smooth and it is simply good looking.
#1 Lightness -> Gingerbread>ICS&JB
#2 Look -> JB&ICS>Gingerbread
In my opinion we should invest more work in ICS.
Sorry for English, I have only sweet 16 yo.
A lot of Nokia phones-> SE K800i -> HTC Magic (Bricked) -> ZTE Blade (RBM ONE) -> ZTE Blade III Pro
MODECOM FreeTAB 2096+ & MODECOM FreeTAB 9704
CUSTOM ROM FOR ZTE BLADE III PRO? O.o