In terms of Sales Figures as well as Longevity, Nintendo Entertainment Consoles and Software titles both come out ahead of Sega produced Consoles and Games.
It was only after the early success of Nintendo's NES in America that Sega decided to move its operations over to the United States and rename their then Mark III, to the Sega Master System and release it in the United States to compete.
Nintendo also followed up their release of the NES with powerhouse franchises that redefined the video game industry, and set standards for development of future video games that many of us developers still follow today.
Nintendo was always ahead of its time, incorporating a lot of new ideas and experimental concepts early on, that we are now seeing take off in next generation titles.
For example, Nintendo released the Power Pad, which was used for games such as Super Team Games where the pad could detect not only impact, but the speed and pressure of the impact, allowing you to race each other in a relay and jump hurdles on screen. Some of the first widely accepted motion sensor technology in video games at the time.
In addition, Nintendo introduced the Power Glove, while not extremely successful in terms of sales, was an innovation of its time simply through concept alone.
Sega experiment as well by attempting to branch into CD formats for their consoles, with the Sega CD and 32 X add-ons to their Genesis, while Nintendo was sticking with cartridges for the SNES, but the sales of the SEGA CD and various other add ons introduced into the market by SEGA failed.
At the same time, Nintendo had considered a CD Add on for their SNES, which lead to a partnership with Sony which fell through as well as a partnership with Phillips, which they abandoned after decided a CD add on would not be well recieved. [Which is a mistake SEGA learned the hard way.].
These failed partnerships were inadvertently the spark of Sony's Playstation and Phillips's CD-i console.
So in terms of successful innovation and execution of new ideas, long living franchises, and first party development. Nintendo by far takes the cake.
While Nintendo was focusing on developing their key franchises like Super Mario Brothers, The Legend of Zelda, Metroid, Castlevania, and others. SEGA was spending their resources and time trying to get gamers interested in Live Action CD format titles such as Dracula Unleashed, and Tomcat Alley.
A risk that never really paid off in the long run.