Blown saves are highly context-dependent. Save opportunities, as well as the margin of lead in those opportunities, are dependent on your team's offense, starting pitching, etc. No one would say Oakland's or PIttsburgh's pen has out-performed the Twins pen this year, even though those teams have zero blown saves compared to the Twins 2. No one would say the Twins pen performance so far is equal to that of Detroit, even though the two teams have an equal number of blown saves. Save percentage isn't much better either. If you want to derive any meaning from these particular stats, the best way is to add saves plus holds (because blown holds also count as blown saves), divided by save opportunities. And also account for raw total opportunities (converting 19 out of 20 is more difficult, and likely a better measure of pen success, than converting 2 out of 2). The Twins are tied for 12th in save + hold percentage, but we're also 4th in total opportunities. That seems to track well with being tied for 6th in bullpen fWAR, and 3rd in bullpen WPA/LI. That's not to say there isn't room for improvement -- 16th in RE24, which is like WPA/LI but based on run expectancy rather that win expectancy.