Hard to say. None of them are particularly strong in the impact department and never really dominated at any given time. But if I had to choose, probably Pink, cause she is more consistent.
P!nk for breaking the cutesy pop star mold for starters and defying the bubblegum craze. Additionally, you hear her signature sound dominating radio. Plus inspiring the next generation of superstars a la ADELE. Also having great balanced WW success with a handful of iconic moments
