A Tale of Two Zooms pt. II
That's a good question - but I've seen more than one person say all the post-Beercan 13/10 element lenses are 'optically identical' and therefore any discrepancies of reviews are incidental, owing to variance in manufacturing or perhaps coating, from 'New' all the way to 'Sony' versions of the lens.
I have owned all the minolta 75-300mm lenses except the big beercan and I can tell you that they are not equal. My copy of the 'new' did disapoint, I do know that my beercan is heavy enough I hate to think of what its big brother would be like.
I am looking forward to the outcome of your tests, sounds like a good excuse to play.