For your concern Id say just grab the deal without any further perplexity and as far as vertical banding or so is concerned then personally I havent seen any bending however, in the very beginning I have seen a short light bleeding at the corner of my screen but after calibrating it thoroughly it was barely visible.
Feature wise LM9600 and LM8600 are identical, the only difference you find in two is in their LED lighting. LG has incorporated nano LED in LM9600 whereas, LM8600 is built-up by using LED Plus technology. Furthermore, today I found a link to LG ongoing offer on its LED TVs
LG Great Home Theatre Combo Offers. Im pretty sure youll be glad with your purchase afterwards.