If we're talking about digitals, then it's neither 2NE1 nor SNSD: both SNSD and 2NE1 did good, solid, in digitals when it comes to song charting - but T-ARA ( in early 2010s) and Sistar did best from 2011-2015.
In every other field, from album sales to popularity and recognition, they dominated supreme in most of 2nd gen era.
