Zito also went, as many Boras clients do, for the most money. He's going to a team that is weak and old, and I doubt he can turn them around himself. He would have been better off going to the Mets, better team, pitcher's park, pitching coach he liked. But $$$ rules.
The Yankees getting rid of Randy Johnson is a great move IMHO, especially if they get some decent propects in return. He hasn't pitched so great for the Yanks, and it certainly seems that he hates NYC.