The main ITV logo is a colour-picking design that changes to suit its backdrop as well as the nature of its programming.
The rebranding came along because ITV wanted to further their relationship with viewers, they now have a consistent identity across everything that they do so they will now be more recognized.
Not many people liked the idea of the ITV rebrand as they felt it didn't fit the maturity of the channel. however a lot of people reacted well to the change as they felt that it had refreshed the channel as a whole and people have adapted from the whole change.
E4 updated the look of their channel for the first time since 2007 (6years ago). They brought Eefer in as they felt that they wanted more communication with the channel, so by doing this they decided that he will communicate by holding a placard that will state the next program coming up. There were no negative reviews on the change of E4 as i think the majority of people liked the idea that the channel was changing.
Eefer had been used before but they hadn't been able to air it for long, so for E4 they got to bring it back and modifies the whole channel aspect. Eefer brings a lot of character back to the channel as you will see him in lots of different areas of the channel.
The upgrade of both of these channels are very different as for with ITV they have changed their font of logo whereas with E4 they have changed a character and used it to their advantage of adding a feeling to the channel for.