When comparing ForkLift 3 vs Double Commander, the Slant community recommends Double Commander for most people. In the question“What are the best Mac file managers?” Double Commander is ranked 3rd while ForkLift 3 is ranked 5th. The most important reason people chose Double Commander is:
You can use same tool in all desktop OS environments.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Best UX/UI'd file manager on the market
It's just a perfectly crafted app, try and enjoy
Pro Rewritten in Swift
Forklift 3 is a significant update from FL2, having been rewritten entirely in Swift.
Pro Optional dark UI
In addition to the default Mac gray UI, Forklift 3 offers an alternate "Dark Mode" featuring light text elements against dark backgrounds.
Pro Connect to and mount lots of storage options
FTP, WebDAV, Amazon S3, Backblaze B2, Google Drive, Rackspace CloudFiles, SMB, AFP, NFS, VNC, etc.
Pro Easily toggle hidden files
Pro Built-in application remover
Pro Multi-platform (Linux, Windows, MacOS X)
You can use same tool in all desktop OS environments.
Pro Source code is available (true free software)
If the developer loses interest there is at least the possibility that someone else will pick up the torch.
Pro Configurable
Lots of options allow you to configure DC the way it suits you best: Tools, Fonts, Colors, Hotkeys, Mouse, Fileviews, Plugins, Layout, Toolbars, Tabs, Icons etc.
Pro Directory Hotlist
Save shortcuts to folders. Organize them in a treeview with submenus. Define a name and sorting for each entry.
Pro Powerful tcmd-like search tool (alt+F7)
Pro tcmd-like multi-rename tool (CTRL+M)
Pro DC uses TCmd plugin API
so you can use documentation from Total Commander for writing plugins. WCX (packer), WDX (content), WFX (file system), WLX (lister).
Pro Closely follows TotalCommander UX
For instance, the 'Settings | Layout' pane is quasi-identical to TCs.
Pro Very sophisticated
Although it is lightweight and simple to use, it can do very sophisticated tasks, like copying files from directories which have a certain extension or file size or have a certain text pattern in them. Also, it's very customizable and stable.
Pro It's that good, you can replace tcmd on windows too
Pro Source code written in (Object) PASCAL
It's all a matter of perspective. I'm not for an argument about IDE's, frameworks etc, but to me that's a big plus. I think it should be a tie, it's either a pro or a con or should that be neither a pro nor a con. It just depends on context.
Cons
Con Like Apple, it does not standardize file size. Mixes up KBs, MBs GBs in the same column which makes it very difficult to review file sizes
Con Like Apple, shows the date of Today's file as "Today" instead of the actual date
Con Does not sync the "selected" folders (i.e. highlighted ones), but the "current" folders (i.e. the top of the visible tree.)
Con Does not show the fixed tree section in the left pane of a dual horizontal panes

Con Apparently only one developer
Con Freeze after mouse double-click on directory list item
Con Much slower on Linux and Mac than on Windows
Con Source code written in Pascal language
But this does not affect users negatively. It's just programmers problem.
Con Not developed anymore for Mac
Con Can't edit files on remote FTP servers
