The Yuko treatment is expensive but worth it if you can afford it, in my opinion. I had it done in Malaysia for a fraction of the price you pay here and I would to have it done again if I could afford it. I don't have particularly curly hair but it is incredibly thick with a natural kink to it which makes it difficult to control. I had it done (partly cos it was so cheap) and it was the best thing ever - I could get out of the shower having washed my hair and without even combing it, it would dry poker straight. They did tell me it was very damaging to the hair but you honestly could not tell from mine as it was so silky and shiny.
Go for it if you have the money - if it goes wrong, it'll grow back!!