If using lst you would only get 10-15% more max on a plant that was vegged for the same amount of time. Lst however allows you to gain much more of an even canopy if you give it a longer veg, whereas a normal plant would just keep growing upwards and only have one main cola. The normal plants lower branches would not get so much light and therefore be popcorn.
long answer shortened:
LST RULES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!