Comment by Froedlich

Wine predates ReactOS. It was basically a FOSS duplicate of Sun's WABI.

I wrote a bunch of software in Borland Delphi, which ran in Windows, Wine, and ReactOS with no problems. Well, except for ReactOS' lack of printing support.

As long as you stay within the ECMA or published Windows APIs, everything runs fine in Wine and ReactOS. But Microsoft products are full of undocumented functions, as well as checks to see if they're running on real Windows. That goes back to the Windows 3.1 days, when 3.1 developers regularly used OS/2 instead of DOS, and Microsoft started adding patches to fail under OS/2 and DR-DOS. So all that has to be accounted for by Wine and ReactOS. A lot of third-party software uses undocumented functions as well, especially stuff written back during the days when computer magazines were a thing, and regularly published that kind of information. A lot of programmers found the lure of undocumented calls to be irresistible, and they wound up in all kinds of commercial applications where they really shouldn't have been.

In my experience anything that will load under Wine will run with no problems. ReactOS has some stability problems, but then the developers specifically call it "alpha" software. Despite that, I've put customers on ReactOS systems after verifying all their software ran on it. It gets them off the Microsoft upgrade treadmill. Sometimes there are compatibility problems and I fall back to Wine on Linux. Occasionally nothing will do but real Windows.