On the plus side, Commander One is performant, with a nice design, clean interface, and useful features. And while I really wanted to like Commander One, there were some feature oversights and other nitpicks that I just couldn't get past, listed below.
Double-clicking folders when using the mouse to open them sucks. Unlike in Finder, there is no reveal/tree mode for folder views. Worse, IMO, there is no column view mode either. So, you're left with a very "Windows" feeling file explorer but even more limited as folders can only be opened by double-clicks (when using mouse).
Doesn't respect the traditional cmd-delete keyboard sequence to delete files. You have to set it up in preferences / hotkeys
I was unable to revert my font choice back to the default system font. i.e. Once you pick an alternative font, there's no going back to the original/default.
Finally, the default mode for sending telemetry data to the developer is "enabled". You have to uncheck the setting in the privacy section of "Preferences".
As I said, most of these are "nitpicking" and, other than adding the finder like view options, easily resolved by the developer. I'll keep watching this product, but I'm not going to use it yet.