Just giving this a hindsight bump. Niemann got off to a rough start this year but has settled down nicely since mid-May. Time to play "which pitcher's line do you prefer?" again:
A: 5 GS, 29.1 IP, 1.23 ERA (!), 18 Ks, 10 BBs, 1.02 WHIP
B: 4 GS, 26 IP, 1.73 ERA, 21 Ks, 3 BB, 0.85 WHIP
Pretty close, but peripherals favor B, especially when you consider his 4 starts include 3 quality starts and a rain shortened start of 3 innings. Pithcer B's line is that of Jeff Niemann since May 18 (B). The other you might recognize as another pitcher's hot streak that has led to people clamoring for him in the Nats rotation - Colin Balester since May 17 (A).