I love my ghd hair straightener and use it several times per week. It heats up quite quickly (in the region of 20-30 seconds) and heats to the perfect temperature for my hair. It's nice and light and feels comfortable to use. I find it less damaging to my hair than other cheaper straighteners, but find that it's definitely worth investing in some argan oil or other heat-protective product. Ghd straighteners are on the expensive end, but I think it's worth spending the extra money to buy a product that does a good job.
This overpriced iron is good if you have naturally fine, soft or wavy hair. If you have coarse, thick hair it will not do the job, or it will take you several passes. This is not unique to the GHD, this applies to ALL CERAMIC straighteners. The Auto shut off and dual voltage is awesome, but it is not worth it if the iron does not provide sleek, durable straight hair. If you have kinky, unruly, poofy hair go with TItanium, hand down!!
For me, the first and still very best of all ceramic stylers [and my dad is a hairdresser too]. It heats up fast, cools down relatively fast, works wonderfully and lasts a long time. In 11 years, I've bought two such stylers. The first one eventually died after 6 years of daily use, rarely skipping a day, while my second one is still going strong. I have no reason to recommend any other styler but this one. My hair is long and very fine.