Imo, the ranking for biggest winners in terms of music career goes:
1 - Kang Daniel (though his digitals on Melon can be better)
2 - Haknyeon (The Boyz)/Nu'est
CFs/Acting/Variety
1 - Kang Daniel
2 - Ong Seongwu
3 - Park Jihoon
It's amazing how far Haknyeon and The Boyz have come!