I worked in the hair industry for a while so I've used a lot of high end flat irons and I got to say, this one did not impress me at all. I'd never used a GHD before this btw (none of the stylists I know have one) but I ended up ordering the GHD classic styler--which btw seems to be the same as the "IV styler"--instead of the CHI Turbo due to the fact that at the time, the GHD was on sale and basically the same price yet it offered more versatility (the turbo has a velvet cover so you can't use it to curl).
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.