I've watched Whitlock many times, but not Davies.
Like you, I'm very impressed with Whitlock's repertoire, but I'm not impressed with how he starts--vice relieves.
His first season, all as a reliever, was/is by far his best: 1.96 ERA, 46 games, 73.1 IP, 81 K's, 17 BB's.
His second year, a mixture of 9 starts and 22 relief appearances: 3.45 ERA, 31 games, 78.1 IP, 82 K's, 15 BB's.
This year, three starts, no relief appearances: 6.19 ERA, 3 games, 16 IP, 11 K's, 3 BB's.