Well,the comparison started out between OS/2 and Windows 3.1 for sure. That's why you heard about it. But, it also was much better than Windows 95 as well. Multitasked better, didn't crash as much. Used about the same resources.
Where Windows 95 beat OS/2 was in the marketing department. Microsoft ran a very good marketing campaign for it. The exclusive preinstall deals with hardware OEMs didn't hurt either. With that advantage, Microsoft was able to make the Win32 API a standard and IBM couldnt hit the moving target to make OS/2 as compatible for Win32 apps as they did for Win16 apps.
As for NT, OS/2 had an advantage in that it ran DOS apps much better than NT 3.51 or NT 4.0 for that matter. DOS apps that needed direct access to hardware had a hard time in an NT environment.
Of course, again, once the Win32 API, much of which was shared between 9x and NT, became standard, this became a non-advantage.
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