Except nobody chose Win95 over OS/2. Os/2 lost the battle, big time, in the Win 3 / 3.1 / 3.11 days.
The reason Windows one was simple:
1) OS/2 was expensive. I mean ludicrously expensive. Typical IBM charged a fortune for the CLI, another fortune for the GUI and yet another bloody fortune for the networking.
2) Windows let you run DOS applications in real DOS by booting into it. OS/2's DOS mode had severe compatibility issues. You have to remember that, back then, there had been no graphics, memory and such APIs, so everyone had their paws in the hardware.
By the time the '95 / Warp "contest" happened, OS/2 was already dead. It was just still twitching a bit......