If you want to switch between apps in the Gnome Shell, you have to take your mouse to the top left corner and all the windows comes to one screen. Some times, you might feel a bit uncomfortable with this method. Some times, you might miss the old panels... In Unity, we have a dock which might be a bit more comfortable than this. What if we add something like that (Without the Unity dash) to Gnome Shell? …
Shell Extensions : Auto Hide The Top Gnome Panel and Get More Space!
One good thing about the new Unity UI is that, if you maximize the window, the side panel will be hidden and the top panel becomes the menu bar of the application. It gives more space to the app! Unfortunately, Unity only comes with Ubuntu and its also not available for people who use Gnome Shell in Ubuntu. But, there's a solution... …