Odd.
I did some test at an Apple store launching Garageband and I ran into beach balls. The i5 was faster with it's HDD. ( this was the 11"MBA however, but the MBA still had Flash instead of HDD )
So I find it a pretty funny statement if you think a MBA will blow away a 15" MBP i5/i7, especially if they will put in a SSD that is so fast, it saturates the SATA connection.