I use GHDs every time I plan to go out, or if I just want to feel nice for the day!
I own both a hairdryer and straightener by GHD. I use them both very regularly (the hairdryer is almost every day, the straighteners will vary).
I can rate them extremely highly as I have never had a problem with GHDs products (I have never had to send any items back or even contact the customer services!).
Although they are quite expensive, the quality matches the price and you will not be let down. They also do deals often on their website (usually 20% off certain products / categories).
Overall, I rate GHD as excellent as I have never had any issues with their products and they are used almost daily. The quality for the price is incredible and I could not recommend any better retailer!