4g is always on when 2g networks is unchecked. battery does drain faster with 3g/4g/lte enabled and when its trying to switch between the signals. i go to university 30 miles away from the city, and there's only 2g and 3g here. without 2g networks enabled, my battery was gone in about 6-7 hours. now with 2g enabled i get about 14-15 hours battery life.
P.s. still trying to solve my "roaming situation"
Sent from my LG-P930 using XDA