I've recently grown White Jem. I got 8 out of 9 that were purple.....lol! And it is some absolutely stellar bud! Potent, sweet tasting and a long lasting high. Ihave not had a pheno type of a strain vary much in potency or bud quality. More likely some environmental factor.
You know I've never liked the dark phenotypes. It seems like whenever I get the alternate phenotype of something that's colored it's actually a denser better quality Bud. Some of the most colorful and interesting looking plants ended up being kind of light and airy for me.
I wonder if @pop22 has noticed this? I think he breeds.