Tom Verducci broke out his calculator and when it was all said and done the Marlins were the most efficient team at getting the most out of the money spent in the last decade.
Here is the final table.
The Efficiency Rating is meant more for fun than for scientific purposes; it's not intended for vetting by the Brookings Institution. It's a shorthand gauge of what kind of bang for their buck teams managed over the last decade.
That said, here are the five most efficient teams of the past decade:
Efficiency Rating Top Five
CPW = Cost Per Win (in thousands) AP = Achievement Points ER = Efficiency Rating
Just go read the whole thing to see how he comes with this. As he points out, the Mets spent $737.5 million more than the Marlins did for the decade and only garnered 4 more wins.