Soriano has assured himself a nice payday for 2010 (about $8-10 million) and has made himself more attractive to other teams by making sure they won't have to give up draft picks for him.
The Braves, on the other hand, will not get the two draft picks Soriano would have brought them had he declined arbitration, and they lose bargaining position in any trade deals because other teams know that the Braves need to move Soriano.
The Braves do not have the available cash to pay Soriano to be a seventh or eighth inning man...they just don't.
Meanwhile, in the NL Central Jose Valverde pitched a perfect ninth for the Astros one more time by declining arbitration. Valverde left about $10 -12 million on the table in 2010 to try to get a multi-year contract from someone else. This assures the Astros of getting at least a couple of draft picks for the departing Valverde, which will help their weak farm system.
Valverde and his agent apparently think that their chances of landing a rich multi-year deal are good. I happen to agree with Valverde's assessment, but I would be terrified while I waited. There are several good free agent relievers available who will be cheaper and several relievers who will be available through trade.
Valverde has to hope that a team will like him so much that they will be willing to give up a first round draft pick for him and then offer him a big contract over a period of three to four years. It's a lot to hope for...and it may end up backfiring.