If you are looking for a different alternative to Windows explorer, macOS Finder, or whatever manager you use in your Linux distro, perhaps Fman will catch your eye. It is designed for power users, it is extensible, it has a system of plugins to add more functions and makes the process of copying files much simpler.
One of the most striking things is that it opens two directories at a time, side by side, so you do not have to open different windows when browsing your files and moving them. It also depends a lot on keyboard shortcuts, for those who prefer not to use the mouse and are faster this way.
Fman was released last year and just came out of the closed alpha on March 1, 2017. It is in active development and although not open source, its creators are committed to release the code if they spend more than six months without making progress so that users do not get stuck on an outdated platform.
Pressing Ctrl + Shift + P displays the list of commands and available keyboard shortcuts. Pressing Ctrl + P shows you the most recent and most used directories. With those two things in mind you can start using it and memorize the most relevant key combinations.
Now, the only bad news about Fman is that although you can use it completely free, a fastidious popup window will appear asking you to buy a license to enjoy it without that hassle. No problem with that, the license only costs 13 dollars and is for life, a single payment.
The problem is that at the moment there are no more licenses available and you have to join a waiting list to be notified when they will be available.