Better S&P ETF: SPY or VFINX?

So, for those of us ready to concede we cannot beat the market after taxes, fees and commissions, there are no-load passively-managed major-index-tracking ETF’s. 2 ways to track the S&P 500: SPIDRs (symbol:SPY) & VANGUARD INDEX TRUST 500 INDEX (symbol:VFINX)

SPIDRs are depository receipts, so not technically an ETF – but  does that matter? Is one inherently better for the individual investor?
Here’s how their profiles stack up:

Expense                                             SPY                    Category Avg
Total Expense Ratio                       0.08%             N/A
Annual Holdings Turnover                     3%                   26.96
Total Net Assets                             62.70B             1.64B

Expense                                             VFINX             Category Avg
Total Expense Ratio:                     0.15%             1.10%
Max 12b1 Fee:                                 0.00%              N/A
Max Front End Sales Load:        0.00%             5.24%
Max Deferred Sales Load:          0.00%              2.61%
3 Yr Expense Projection*:         $48                  $573
5 Yr Expense Projection*:         $85                  $868
10 Yr Expense Projection*:      $192                $1,726

Both are cheap, and both let you buy the equivalent of the same great index.

Is there some reason to pay the .07% extra to buy Vanguard instead of SPIDRs?

The Lipper Avg. Scorecard is similar for both EXCEPT: SPIDRs only get a 2 out of 5 for Tax Efficiency whereas VFINX gets a 5 out of 5.

Another Difference: Vanguard has a 6% annual turnover while SPY’s rate is 3%. Could this be because VFINX re-allocates twice as often? Is this better for the investor?

These are not rhetorical questions I really want to know.

Please Advise.