Since 2007 when Bailey came into the league, Arroyo has a WAR of 7 to Bailey's 4.8. If you compare them side by side since 2009, which was the first year Bailey logged at least 100 innings, Bailey has a WAR of 4.7 and Arroyo has a WAR of 2. There's obviously room for disagreement, but I'm going with Bailey on both track record and future expectations.