By Rabbi Dovid Markel
The advantage of the Bal Teshuva (penitent) over the Tzadik (righteous), is the sin itself. The very imperfections make him more perfect. Knowing sin, yet abstaining, expresses a tremendous depth the tzadik in unaware of.
This is the advantage of the subduer of his evil inclination over the perfect saint. The subduer of evil reaches a depth of his soul that the righteous person can barely dream of.