EE did launch today and there is supposed to be a huge difference from 3G where you see speeds of 7megs if youre lucky to over 30 on LTE, but EE is the only carrier that today has launched LTE (4G) in the UK so wait for other carrier to offer it as well see how they do as EE are using old networks to offer the LTe so I dont see it being so amazing atm.
There really is'nt a comparison between speeds of the 2 networks...., 4g is by far faster.