I know that the proof of the pudding is in the eating, so here's why I love this so much: I have incredibly thick, naturally curly hair that is prone to extreme frizz. Spit on it and it turns into an afro. Don't believe me? Here's a shot of my hair in all its natural glory - dried naturally and brushed. Brace yourselves.
See? Big ball of fuzz. Now I know I could spend ages blow-drying it with such-and-such product and special nozzles, blah, but seriously - I haven't got the time to do that a couple of times a week. I wear my hair up a lot, but when I want to wear it down - well, I'm not going to go anywhere with it looking like the above!
Behold, after only 30 minutes (amazing how quick this thing is, it used to take me nearly an hour to straighten my hair with my old one) - and using no product whatsoever.
On average, it stays straight a good 2 days when I finish off with a tiny bit of hair oil or serum on the ends. I've been using this at LEAST twice a week since I bought it, and my hair hasn't suffered at all. It's not fried like it was when I was using the GHD, and it's not brittle or breaking. I'd still recommend the use of a hair treatment once a fortnight - or a leave-in conditioning treatment (L'Oréal do good ones, in little tubs - find them beside the shampoo & conditioner in any supermarket) once a week.
I only wish I had this as a teenager, my ponytail was so thick that I could never wind a scrunchie round it more than twice.
Verdict: Well worth the money (I got mine on sale last year, I can't remember the price) for those of us who are prone to frizzing.