No one had addressed the original question - a sonic comparison of the 5SE and the 28.
I have not heard them in a comparison test. What I do hear sometimes is that "the new LS-xx" sounds better than than the Ref-y froma zz years ago. And not just from dealers either.
I think the only way to answer this is by direct comparison using a blind test on top quality source material.
I am just going to be happy with my LS25 Mk II (at least for a while)