I bought these straighteners after talking to my hairdresser about why my hair keeps breaking. She advised me to try Remington Keratin Protect Intelligent Ceramic Hair Straighteners S8598.
Got these and tried them out immediately. I set them to 180 degrees and they heated up in seconds - at least on par with GHD speed. Then I used them, and WOW! I could tell the difference immediately, mostly from the fact that the straighteners didn't make a sizzling sound or let off any smoke, which my GHDs did. I'd convinced myself that those things were NORMAL (I know...), and caused by the heat protection spray I used rather than the fact that my hair was burning. FYI, I followed exactly the same process with these, by spraying the heat protector all over and leaving it to soak in for a couple of minutes before straightening.