So it would seem the consensus here is that the Saturn was the biggest fuckup of the four, though Xbox One also garnered a lot of votes.
N64 meanwhile got off the most lightly, with the least number of people crowning it biggest stumble.
It would seem a major factor was how well the system in question satiated the fans in spite of its commercial missteps; PS3 and N64 for instance are generally looked back upon fondly for their killer exclusives, while Saturn and Xbox One are somewhat more controversial.