I hate comparing trades and insinuating different deals can be compared, but since Adam Schefter did it, I'll just go with what he said.
So the Seahawks essentially traded away a fourth round pick for Lynch then received one back for Branch. Through the transitive property, one could say Seattle traded Branch for Lynch.
The end result is the Seahawks only losing a conditional late-round pick for Lynch after gaining New England's in return for Branch. A week of wheeling and dealing for Seahawks GM John Schneider finally comes to a close with a successful ending.