I use my S3 for viewing films, surfing and shopping. It's OLED screen is unbeatable and it runs very smoothly. It's on par with the latest IPAD according to independent testers Which. I have the 8 plus as my phone.
Samsung have the best mobile screens period.
LG mobile OLED is inferior to Samsung but it's TV OLED technology is top-notch.
Slightly off topic, I have a 4K LG TV(non-OLED) and that has amazing screen.