Tough call. Sony has the edge in terms on signal processing. Better shadow handling, slightly better motion handling. LG is less aggressive on the light limiting functions such as auto dim and ABL.
Then there’s the operating system. It just might come down to your preference in user interface. I struggle to like the pointer on WebOS, but you might feel differently. I would advice you to try both systems out. It doesn’t have to be on these specific models, but Android should be tested on last years model just to make sure you don’t get fooled by the speed of this years lineup. WebOS should feel the same regardless of which model you try out.