hey folks, is there any advantage of buying from costco like extended warranty or easier return/replacement process over buying from Sony directly?
Also, would there be any issue down the line with warranty claiming if I use my friend's Costco account to buy the TV for myself?
Doesn't matter which Costco account you use as long as have receipt (or they maintain their subscription).
Anecdotally you're going to get both positive and negative feedback for both buying from Costco as well as Sony so doesn't really matter. Pick the one cheaper/more convenient for you.
I got great service from Sony on a TV bought from them directly that died 2 years 4 months in. They replaced it with an upgraded model and size within 3 business days with no fuss. They even sent me the new one before they collected the old one. Others have had really poor service from Sony support. You may or may not get the same level of service so not worth fussing about.