I'm on the other side. I'd rather take Darvish, who is 4 years younger. Verlander's 2016 was a beautiful return after a lost 2014 and a short (and devoid-of-Ks) 2015, but relying on that again for his age 34 season feels pretty risky, too. And on Ks, Verlander has averaged 8.5 K/9 for his career and only made it to 10 twice - 10.0 in 2016, and before that 10.1 all the way back in 2009. Darvish has never had less than a 10.4 season and has averaged 11.3 for his career.
Verlander tosses a lot of innings and that can reduce the K gap, but that age 34 number starts to put some more