Is ReactOS capable of running all the Windows software OK already? I'm curious if I can actually use it instead of Windows whenever I need a Windows VM.
Wine tends to have far higher compatibility, and the operating system it runs on top of is mature too.
ReactOS is a cool project, but it's an alpha-stage complete operating system with bugs as basic in nature as you shouldn't even expect the file system to live long without being corrupted, or the OS crashing constantly. Not to mention they primarily focus on Windows XP compatibility, Vista and newer software is generally unlikely to work.
