MMMM thats a hard and tough question to answer. Many have sayings and theories but know one can really make that judgement either by trying or testing every strain. This is something that everyone would love to know... I think you try to find out whats a really potent strain in your favor meaning. Do you prefer mostly sativa(head HIGH)? mostly indica(Body High)? or a mixed combo(head&body high)? A good and strong mainly indica I wound have to say white rhino, cant really comment on the rest. There are good strains like you also mentioned as well as White Russian, Ak47, warlock, ice, C99,Haze. I'm getting Reservoirs Sour Diesel IBL.. thats suppose to be not only potent as hell but a nice flavor and smell. I was also looking at either MK-Ultra or Kushage both look like kick ass strains by TH seeds.