If 80% of your time with the TV is gaming, then the F8000 may be a tough recommendation. Its input lag is not great. Typically you want under 40ms, but the F8000's game mode only lowers it from 100 to 81. Renaming a source to PC lowers it to around 50, but that locks you out of using Smart LED, the setting responsible for keeping blacks deep and consistent. The same trick apparently lowers the F7100's input lag to 40, but I have to imagine it disables similar settings. I'm not sure how well the LG does.
I hate mentioning this so much on the board, because the F8000's design and its picture are gorgeous. 3D is also excellent. If I had to choose one of those three it would be one of the Samsung panels, though. Samsung tends to have better motion performance and uniformity over LG.