I've been using GDHs for year. But do make sure you get them from a geniune retailer (not online).
My sister picked up a 'genuine' pair on holidays in Egypt and was then shocked they were pretty cr@ppy.
My own pair died on me two years ago and I contacted GHD as I was pretty concerned as they'd actually gone on fire on me. I sent them back so they could check the serial number. They then sent me a mice apology letter and replacement GHDs which have been working fine ever since. They had to verify the were genuine GHDs first though. However their customer service were top notch.
The new pair were much better than my last as they were the latest brand and I've been using them for to years without hassel. They are expensive but once you look at the price per use, it's not that much as they are indeed better than the others and last for yonks.