oled has faster refresh(but you controller driving it this fast), black that is black(since each subpixel emits its own light) higher contrast(MUCH higher). OLED also has VERY wide viewing angles.
It has downsides too since the pixels have a life span so blue will start to fade first. They use more power to display bright images and the same sample and hold that LCD uses will cause perceived motion blur. Each frame sits on screen for a fixed time, even if the change is fast you will still see blur. Black frame insertion or some kind of strobe could fix this at a cost of brightness(something oled may now always have to spare).
Overall OLED is great, but it will be a long time for prices to come down.