LG says that according to independent testing by UBI Research, their 55EA9800 curved OLED TV is superior to Samsung's KN55S9C in several aspects. So first of all, LG display's OLED TV is much smaller. It weighs 17.2 Kg while Samsung's TV weighs 32.8 Kg. LG's TV is also 8.2 mm slimmer (4.3 mm vs 12.5 mm) and has a narrower side and top/bottom bezels.
LG says that this is because their TV design is much more simple. They say they use 952 circuit components while Samsung uses 3382 components.
LG also says that they earned a better energy efficiency rating in Korea, as their TV consumes 265W while Samsung's S9C consumes 295W.
Of course for more people, what really matters is the image quality and not the number of components. Currently only HDGuru tested both OLED TVs and they say that while both offer the best image quality they ever saw, they liked the Samsung's OLED better. Samsung's TV is also currently cheaper ($8999 vs LG's $9,999).