General Rooting or updating

view story

http://androidforums.com – Hi. I'm new in the Android phones and these days I'm going to buy Sony U so I wanted to ask you few questions... Why do you root your phones? What is it that you acctually get when you root phone? Does the phone work faster? Is it possible to root Sony U to Android 4.1? What version of Android is faster 2.3 or 4.0. I know that this phone has only 512 MB of RAM so is it good idea to update to 4.0? And the last question is, is it better to root and update phone know or to wait for official ICS update? Thanks and sorry for my Engrish. (General)