For anyone having the lag delay, did you disable S-Voice from using the center button yet?
Once you do that you'll notice a very slight increase.
The center button is set to double tap and launch S-Voice.
The delay when you tap the center button ONE time is due to it waiting
for the SECOND tap.
Disable S-Voice from using that button.
Moving to Issues reported on the Note 2
....subject is the screen lag.