New York makes out best of the two deals because the Yankees could use the extra offense provided by a reliable Gary Sheffield. The Yanks already have good enough pitching (although there is always room for improvement).
On the other hand, Boston picks up Schilling who has been a great pitcher in the latter stages of his career. But at this point, it appears to me that Schilling is on the downside of his career. He still shows signs of greatness in some outings, but overall, he has shown a high level of inconsistency over the past couple of years.
Once again, the Yankees get the best trade.