Here are some numbers I looked at this afternoon. Through 98.2 IP the Nats starters have an ERA of 1.82, WHIP of 0.86, and a K/BB rate of 4.55. In 1997 Pedro Martinez had a 1.90 ERA, 0.932 WHIP, and 4.55 K/BB. I don't think the rotation can keep this up all season, but that gives some idea of how good they have been thus far.