Hair Straightening for Thick Curly Frizzy Hair

My friend Monica with a quite thick, curly hair (and a little frizzy), she was bored with her curly hair.
 
She was going to get a hair straightener, but have no idea which ones are the best.
 
She asked to me "I was thinking about GHD hair straighteners? But I have heard a lot about Chi and Hai and others. What are your views on the best hair straightener? I want an amazing one that doesn't damage my hair, and leaves my hair super straight all day. Also they have to last long, with a good guarantee. I am willing to pay any price! What are your thoughts?"

Well, from her words I could get these information:
1.She was puzzled with which is the best hair straightener brand.
2.She wants the one which could not damage her hair, and leave her hair super straight all day.
3.Long and good guarantee.
4.She doesn't care the price! :)

Here is my suggestion: The best for her is Sedu Hair Straightener, it has great reviews because it performs great. It has nothing to do with Folica owning it. My review and that of many of my friends is on that site; and no they did not pay me or gave me anything in exchange for my review (like other sites claim) I have tried the different flat irons and this one is absolutely awesome. For her hair nothing works like it. Not the Chi, not the T3 tourmaline, not that $398 Bioionic piece of crap that I'm still so upset about buying, not my $150 Adam Sphere Super Star, not the $100 Helen of Troy etc. You see I have actually tried them, so I can tell you what worked the best.