I was torn between picking one of those exact two panels as well. I ended up getting the Q9 based on the location in my house. The TV is in my living room where my wife likes to keep the windows open during the day, the brightness is about twice as bright as the C8. I also do some gaming so I was worried about burn in with some games. All this being said I would base your decision on the type of content you watch and the location in your house. Either way you will be walking away with a great television.
I do some light gaming on the TV mosty PC now and consume tons of content on 4k streaming and 4k bluray.
I would suggest you get a nice sound bar as well, as almost all these new thinner panels have speakers that dont do the picture justice.