Is the Ozon Titanium Flat Iron better than the TUHI or the Chi?

I have really thick hair, & it's puffy. I need to know which one will give me smooth, shiny hair, but not make it look greasy. I want really straight hair! http://styletips101.com/wp-content/uploads/2009/10/straight-hair.jpg <-- Like this kind of straight for 8th grade. PLEASE HELP!