Reg touchscreen lag, I mean the fact that after pressing the "Power" button, the display turns on but it takes some time until the touchscreen starts to work. It's not a really big issue, but it's somehow nicer on other phones that you can directly use the touchscreen. However, I am used to it now.
BTW: Whereas in previous stock roms, after turning the phone on, you could see the homescreen for a short time before the lockscreen became visible, this issue has been fixed in the new 10C build
So it seems like LG is not totally uninterested in satisfying their customers.