Nope, didn't kill my hair.
Hair was colored black.
Guy who does mine is a trainer - its not cheap, but lasts until your hair grows out.
Once this bub is born and I've stopped BFing I'm getting it done again.
My cousin spent $100 and an hour on her "straightening" did jack all...
My hair (shoulder length) took about 7 hours.
You pay for what you get.