Hydrience...not only does it last but it's (out of all the ones that I have tried) the one that least damages my hair. After rinsing it out, I can run my fingers through my hair BEFORE applying the conditioners!
I agree with the othet poster that said Garnier last longer. I also think lighter colors last longer and darker colors fade easier, in my opinion and experience.
Red. It's a pigment that stays in the root, even when it fades. Blonde is a bleaching agent, which means it strips the hair follicle of its natural color entirely. But be wary of it-straw hay is sometimes a consequence of bleaching.