Fiwi is a compact application that quite simply helps you move files and folders via 2 symmetrical Finder windows.
Fiwi provides the 2 symmetrical Finder windows on the desktop, side by side in columns or alternatively one on top of the other in rows. For easy access, it's best to drag Fiwi into the dock (so you can access it even if no Windows are open) or you can move it to the left sidebar of any Finder window, under Places, just above the desktop icon.
Whether Fiwi is more useful that just transferring files simply by dragging and dropping or using the "Send to.." option is debatable. It takes some getting used to although when you have, you can easily see that it could speed up your work flow, particularly if you're transferring multiple files between the same folders.
Fiwi is an interesting alternative to standard file management on a Mac although whether it will be useful to you depends on how regularly you transfer files.
