Anyone from Audio Research able to shed some light on the question?
That will not address the question either. Where do you think the "rumors" that the LS28 is 'superior' to the Ref 5SE are coming from?
That's like asking the fox if he will eat any of your chickens if you let him into your hen house, and expecting an honest answer.
ALL manufacturers will claim that their new current lineup is superior to their older, discontinued lineup, or they don't stay in business very long.
The marketing idea, is to sell current product, not discontinued product.