After a long time, i am blogging through this post.
So...I am running ubuntu since 2010(from version 10.04) so after 2 years it was totally awesome experience with ubuntu.
In newer Ubuntu(Ubuntu after v11.04) , It introduced new Unity UI for rich desktop experience.
GNOME 2.X was used in Older ubuntu and Fedora is using GNOME shell(after version 15).
So, I have seen many post related comparison of older GNOME with Unity and Unity vs GNOME Shell. GNOME Shell and Unity both look like a same but both have its own functionalities.
But As per my experience, Unity is awesome thing and it increases the productivity. Lets see how...
OLD WAY OF GNOME:
Suppose I want to run open office then I will go into application menu and then office then will run any open office application after that I found that lets check the mail and I will go to again Application menu then Internet then Thunderbird or any email client. In short, Each and every time I have to shift from keyboard to track pad(touch pad).
LETS SEE NEW WAY :
Above task can be done in easy way with latest ubuntu.
SUPER+ Libre... Navigate-> ENTER
SUPER+Thun..Navigate->Enter (BEST WAY TO USE HUD IN UBUNTU 12.04 : ALT+ emai..-> ENTER)
ALT+cha..-> Enter (It will open chat application called empathy)
So,No time to go on track-pad (touch pad), Its simply awesome.
Now, you can understand how Unity is useful then older GNOME .
Unity is specially design for keyboard lovers and you are using linux so sure you will be keyboard geek otherwise you wont try linux.
HUD IS ALSO FOR KEYBOARD GEEKS.
UPDATE: If you want to see shortcuts on ubuntu 12.04 then press SUPER and hold.