This is just my take on the LS vs. A8 debacle, but I really don't care for the new A8 and I think that if you parked an LS 500 next to one, most people would agree. The Audi formula of ultimate simplicity and restraint is hard to justify on an $85,000+ purchase, IMO. I know the new A8 is packed with great features and technology, but if I am going to spend that much money, I want something that looks and feels - jumps out at you - as being special. I do not get that vibe from the Audi.
I hate saying this because it smacks of "internet fanboy" but the exterior and interior shapes of the A8 are, at first glance, very similar to some lesser VW products in overall design. I know the detailing is entirely different, but the A8 doesn't look wholly different from an A4, or the new Arteon, or much else in VW's stable. The LS 500 is a completely new animal and I don't think it will ever be confused with much else.... furthermore, it looks ~10 years newer than the A8, IMO.
If you want traditional luxury, the LS does a better job.
If you want new age luxury, the LS does a better job.
If you want slick tech integration, the A8 seems to do a better job.
If you want athletic and sporty, the LS seems to do a better job.
If you want something that's going to make a more unique statement about you as a buyer, the LS does a better job.
Just my .02 but I can't look at the pics above and determine how any person with functioning eyeballs could choose the A8 over the LS based on the interior and/or exterior.