They're pretty much the same pitcher, Perry just had options, Balester didn't.
Perry - 4.64
Balester - 4.65
I'd rather have the pitcher with options and the one that hasn't already been a huge failure here. Balester never lived up to potential and does not have the command to ever pitch successfully in the Majors. Perry is what he is, a AAA reliever who can fill in as the last guy in your MLB pen if needed but there are no high expectations for him which is fine.