Max Scherzer, best true free agent signing....ever?

The case can be made.  Since signing his 7-year, $210m deal with the Natinals back before the 2015 season, he's had quite the remarkable run.  91-47, 2.80 ERA, 0.962 WHIP, 151 ERA+, 2 Cy Young Awards (with 3 other top-5 finishes), 6 All-Star Games with last year being the lone exception when there was no All-Star Game, and of course, most importantly, the ever-elusive WS ring.  

Most free agent signings either have a few good years and then regress, or the injuries start to take their toll.  Other free agents just flat out blow, like Jason Bay.  I've been thinking about it and there are only a handful of true FA signing who have excelled as consistently from day 1 through the end the way Scherzer has.  And I mean an actual free agent, not a homegrown player that your team signed to a long-term deal, or someone acquired in a trade and then subsequently extended.  

Others in the conversation would be Manny Ramirez with the Red Sox (.999 OPS in 8 years, 2 rings and a WS MVP award), A-Roid (split between 2 teams though), Randy Johnson with the D-Backs (although he did have a down year in 2003), Greg Maddux with the Braves, Barry Bonds with the Giants. 

I know I'm missing some, so what say you, sports board?