We were having this discussion in the Angels/Tribe series thread, but didn't want it to get buried quickly after the series ends in an hour or so.
Best starting pitcher of the 30 years, I threw in most of the great guys I could think of off the top of my head and also threw in Kluber just for comparison sakes. I do know that I left off Mussina, Schilling, Santana, Sabathia, and probably a few other guys, but I got burned out of looking up stats:
Greg Maddux (1988-2008): 347-209, 3.06 ERA, 107 CG, 34 SHO, 3250 K, 1.12 WHIP, 1.7 BB/9, 6.1 K/9
- 4x Cy Young, 8x All-Star, 18x Gold Glove, 4x ERA title, 1995 WS Winner
Maddux prime (1992-1998): 127-53, 2.15 ERA, 56 CG, 19 SHO, 1286 K, 0.96 WHIP, 1.4 BB/9, 6.9 K/9
- 4x Cy Young, 6x All-Star, 7x Gold Glove, 4x ERA title, 1995 WS Winner
Tom Glavine (1988-2008): 303-199, 3.51 ERA, 56 CG, 25 SHO, 2587 K, 1.31 WHIP, 3.0 BB/9, 5.3 K/9
- 2x Cy Young, 10x All-Star, 4x Silver Slugger, 1995 WS Winner, WS MVP
Glavine prime (1991-1998): 140-64, 2.96 ERA, 35 CG, 14 SHO, 1198 K, 1.24 WHIP, 3.0 BB/9, 6.1 K/9
- 2x Cy Young, 6x All-Star, 4x Silver Slugger, 1995 WS Winner, WS MVP
Pedro Martinez (1992-2009): 219-100, 2.93 ERA, 46 CG, 17 SHO, 3154 K, 1.05 WHIP, 2.4 BB/9, 10.0 K/9
- 3x Cy Young, 8x All-Star, 5x ERA title, 1x Triple Crown, 2004 WS Winner
Martinez prime (1997-2005): 149-53, 2.47 ERA, 39 CG, 13 SHO, 2196 K, 0.97 WHIP, 2.1 BB/9, 10.7 K/9
- 3x Cy Young, 6x All-Star, 5x ERA title, 1x Triple Crown, 2004 WS Winner
Roger Clemens (1988-2007): 294-162, 3.13 ERA, 82 CG, 36 SHO, 3978 K, 1.17 WHIP, 3.0 BB/9, 8.6 K/9
- 5x Cy Young, 10x All-Star, 6x ERA title, 2x Triple Crown
Clemens prime (1988-1998): 173-102, 2.90 ERA, 78 CG, 34 SHO, 2459 K, 1.16 WHIP, 2.9 BB/9, 8.8 K/9
- 3x Cy Young, 6x All-Star, 5x ERA title, 2x Triple Crown
Of note with Roger Clemens, he pitched at a high level in both 1986 and 1987, which were not included in this study because those seasons were more than 30 years ago. Over those two seasons, he went 44-13 with a 2.74 ERA, 28 CG, 8 SHO, 494 K, 1.08 WHIP, two Cy Young awards, and an AL MVP award.
Clayton Kershaw (2008-present): 149-69, 2.37 ERA, 25 CG, 15 SHO, 2218 K, 1.00 WHIP, 2.3 BB/9, 9.8 K/9
- 1x MVP, 3x Cy Young, 7x All-Star, 5x ERA title, 1x Triple Crown, 1x Gold Glove
Kershaw prime (2011-2017): 118-41, 2.10 ERA, 24 CG, 14 SHO, 1623 K, 0.91 WHIP, 1.8 BB/9, 10.1 K/9
- 1x MVP, 3x Cy Young, 7x All-Star, 5x ERA title, 1x Triple Crown, 1x Gold Glove
Corey Kluber (2011-present): 90-54, 3.07 ERA, 17 CG, 7 SHO, 1347 K, 1.06 WHIP, 1.9 BB/9, 9.7 K/9
- 2x Cy Young, 3x All-Star, 1x ERA title
Kluber prime (2014-present): 77-44, 2.80 ERA, 17 CG, 7 SHO, 1152 K, 1.01 WHIP, 1.8 BB/9, 10.1 K/9
- 2x Cy Young, 3x All-Star, 1x ERA title
Max Scherzer (2008-present): 156-80, 3.22 ERA, 9 CG, 5 SHO, 2359 K, 1.10 WHIP, 2.5 BB/9, 10.3 K/9
- 3x Cy Young, 6x All-Star
Scherzer prime (2013-present): 104-38, 2.80 ERA, 9 CG, 5 SHO, 1530 K, 0.98 WHIP, 2.2 BB/9, 11.0 K/9
- 3x Cy Young, 6x All-Star
Roy Halladay (1998-2013): 203-105, 3.38 ERA, 67 CG, 20 SHO, 2117 K, 1.18 WHIP, 1.9 BB/9, 6.9 K/9
- 2x Cy Young, 8x All-Star
Halladay prime (2002-2011): 170-75, 2.97 ERA, 63 CG, 18 SHO, 1699 K, 1.11 WHIP, 1.5 BB/9, 7.0 K/9
- 2x Cy Young, 8x All-Star
Justin Verlander (2005-present): 199-120, 3.39 ERA, 24 CG, 8 SHO, 2620 K, 1.17 WHIP, 2.7 BB/9, 8.7 K/9
- 1x MVP, 1x Cy Young, 7x All-Star, 1x ERA title, 1x Triple Crown, 2017 WS winner
Verlander prime (2009-present): 153-86, 3.18 ERA, 21 CG, 6 SHO, 2143 K, 1.12 WHIP, 2.5 BB/9, 9.2 K/9
- 1x MVP, 1x Cy Young, 6x All-Star, 1x ERA title, 1x Triple Crown, 2017 WS winner
Randy Johnson (1988-2009): 303-166, 3.29 ERA, 100 CG, 37 SHO, 4875 K, 1.17 WHIP, 3.3 BB/9, 10.6 K/9
- 5x Cy Young, 10x All-Star, 4x ERA title, 1x Triple Crown, 2001 WS winner, WS MVP
Johnson prime (1993-2004): 197-80, 2.78 ERA, 76 CG, 32 SHO, 3343 K, 1.08 WHIP, 2.8 BB/9, 11.8 K/9
- 5x Cy Young, 9x All-Star, 4x ERA title, 1x Triple Crown, 2001 WS winner, WS MVP
Here's how I'd rank them. I'm going to caveat by saying I can't stand Clemens, so I'm probably dropping him farther than the numbers deserve:
1. Randy Johnson
2. Greg Maddux
3. Pedro Martinez
4. Roger Clemens
5. Clayton Kershaw
6. Justin Verlander
7. Tom Glavine
8. Roy Halladay
9. Max Scherzer
10. Corey Kluber