I've just installed Ubuntu again after 2 years (forced for internal reasons). I see that Unity Desktop Environment advanced a lot, and it's quite usable now.
However, I've come from Gnome desktop. And, I really miss the beautiful look of native GNOME Files (Nautilus):
Is there any way to install Files with native GNOME 3 titlebar?
Install
gnome-tweak-tool
Open it
Change the theme to Adwaita, Icon theme to Adwaita and Cursor theme to Adwaita as well.
The default Gnome look will be restored.