Going by some views that I have came across, there are different views about Unity and Gnome Shell.
It seems while some people like Unity, there are also a good number of people (including self), who like Gnome Shell. So for new users who might wonder the reason behind the existence of different UI’s (user interfaces), I thought to present my views.
From my limited experience of using different operating systems, I have hardly seen any OS which offers such different UI’s which work just fine. Here in Ubuntu (that’s the distro I use), we have choices and as an end user I don’t think anyone can have issues when given choices.
Overall I see this as an opportunity for users to get to know the good things of different worlds and also choose the one that suits their requirement. It’s a great thing.