The risk of burn in isn’t as great in the newer models as it used to be, I guess plasma was the same where the newer ones also were less prone to burn in.
I don’t own it just yet, but personally I’d be aiming for the LG C8. The B8 is cheaper, but the C8 uses a better CPU (same one as the E8) and is supposed to have better colour correction also. I’m not sure that will really make that much of a difference to you from the B8, but I’ll be going with the C8 just to be future proof. I looked at the E8 and it just seems to have better speakers, which isn’t a priority as I can use a soundbar or another set of speakers anyway if that was important to me.