A Kohler 20kW is generally a solid choice, they've got a good reputation for reliability!
20kW is also a pretty decent size and should be plenty for a cabin, unless you're running a bunch of high-demand appliances all at the same time like a well pump, AC unit, and electric stove.
It would be helpful if you figure out your cabin's total power needs and look at the wattage and add it all up.
Don't forget to account for the starting surge on motors. You can usually find a calculator online for this.
If the numbers look good, the Kohler should serve you well!
Just also make sure you can see it run and maybe get a history on its maintenance.
