You’re so right on both counts.
However, Westbrook’s efforts are better than Harden on the defensive end. He’s top 10 in defensive win shares (only .1 behind Kawhi Leonard and virtually tied wth DeAndre Jordan). He’s #2 in Defensive Box Plus/Minus (4.7), behind only Draymond Green (4.9). His defensive rating is in the top 15. He has a slight edge in steals, while Harden has a slight edge in blocks.
My vote goes to Westbrook.