I still think Rivera gets overrated based on being on Yankee title teams. If you look at 1998 through 2003, a span in which the Yankees appeared in 5 World Series in 6 season, the largely unheralded Rob Nen actually had more fWAR than Rivera (12.9 to 12.4).
This certainly doesn’t make Rivera bad at his job by any stretch, but I think his being the first unanimous choice for Cooperstown over, say, Cal Ripken or Junior Griffey, somewhat laughable. If Rivera was on the Giants like Nen was, would he have been voted in unanimously?