It is a difficult choice, LOL. I used to have 2012 Avalon Limited and I do own 2017 LS 460 now (they are different years from what you looking for but the same generation). These are both great cars and it is really "case-by-case" scenario. Why don't you split it right in the middle and get ES350 of the similar year? I used to have ES350 UL between my last Avalon and the LS460. Great car, mechanically identical to the Avalon, just as reliable as 3rd gen Avalons if not better but better quality interior and it is quieter. As for the sound quality goes, if you want better audio system you need to look for the Avalon Limited, which comes with JBL Synthesis or the Lexus that comes with optional Mark Levinson audio. Another thing to consider is a cost of maintenance. Old ES350 and old Avalon are both fairly easy and cheap to fix, old LS460 on the other hand is going to cost a fortune to fix if something goes wrong. That's why old LS460 might be as cheap to buy as the old Avalon (if not cheaper).