Loreal Color Rays?

I'm interested in the purple color, and I have dark brown hair. A couple questions:

1) Does this particular hair color system wash out over time, or does it have to grow out (permanent, semi-permanent)?

2) Any personal experiences with the product/ color, good or bad?

Thanks!

Loreal Color Rays?

Color Rays isn't permanent. I wouldn't use it though, because those kits never work well. A friend of mine used a similar kit that was meant to give her hair a certain tint, and her hair looked like someone had thrown up on it.