i've never heard a T3 vs. GHD review, but my hair stylist, who just recently moved to Athens after doing hair in Manhattan for quite a while, says that she never believed the GHD hype until she started working at the salon I go to about two months ago (they use GHD products but they don't force her to use the iron, she can use and recommend whatever she thinks works best, it's a very cool salon) and got to try it on her clients, and she said she'll never use anything else. I'd imagine doing hair in Manhattan would allow her an opportunity to try a lot of different things, so I believed her review of the GHD and tried it, and WOW, what a difference. It's expensive, but the 20% sephora code will save you almost $50. Now is the time to try!
And minami, the GHD products may not have worked for you because the different ones are all formulated for very specific hair types. I had my stylist recommend some for me because I was having trouble figuring out which ones were appropriate for my hair type, and I've been really happy with what I got.