I'm not going to say much about "Sunflower File Manager" because there's a link to a good review, other than it's superb and definitely worth downloading.
It's free and open source. Take a look, I think you will like it too.
Quote: Craciun Dan | March 30, 2014
"Although it describes itself as a minimalist file manager, I have only words of praise for Sunflower, since it rather gathers a lot of features in a compact interface, and I do believe it needs a bit more attention. Sunflower is a twin-panel file manager with a somewhat different approach compared to standard GNOME/KDE/Xfce file browsers, written in GTK with several notable features and support for plugins. By default, Sunflower shows a twin-panel browser with files and folders listed in a detailed view mode."
Link to full review: http://www.tuxarena.com/2014/03/a-look-at-sunflower-file-manager-ubuntu-installation/
There's an easy download too, for other popular Linux flavours, besides Ubuntu.
Link to Download: http://sunflower-fm.org/download
Link Home page: http://sunflower-fm.org/