The original version of Adobe Acrobat included two ways to create PDF files: Adobe PDF Writer and Adobe Distiller. The Adobe PDF Writer was a Windows printer driver that directly converted Windows graphics commands into PDF. Adobe Distiller was a Postscript to PDF converter. If you printed to the Adobe Distiller printer, it first converted the graphics to a Postscript file, and then Adobe Distiller converted the Postscript to PDF. The two step conversion processes used by Adobe Distiller was slower, but usually produced smaller and better quality PDF files.
The original version of Win2PDF released for Windows NT in March of 2000 was very similar in architecture to the original Adobe PDF Writer. Win2PDF also directly converted Windows graphics commands into PDF, and was very fast when compared to Adobe Distiller.
Starting in Adobe Acrobat 6, Adobe discontinued support for Adobe PDF Writer and Adobe Distiller became the default "Adobe PDF Printer".
Starting in Win2PDF 7, the architecture of Win2PDF changed to make use of the Microsoft XML Paper Specification feature that is built in to Windows Vista, Windows 7, and Windows Server 2008. Win2PDF 10 now creates an XPS file, and then converts the XPS file to PDF. This allows Win2PDF 10 to handle fonts and graphics better than older versions of Win2PDF.