I used to use Tresemme Heat Protectant, but since I have been doing no silicones for a while now I had to find a new heat proctectant when I started straightening my hair again this fall (I do air dryed hair all summer to save it from the heat), since the Tresemme contains silicones. I decided to give this product a try since it was silicone free and affordable and I like it so far! It has a great scent, dries with no residue, and makes my hair shiny and soft! I can't attest to it's difference from the Chi since I have never tried the Chi but I like the GVP version.
The first time I used the GVP thermal protection spray, which I bought at Sally's, I thought it worked pretty well but I noticed my hair wasn't as shiny as usual. After 5 times of using this, my hair looked completely fried -- super dry, frizzy, ugly.
The only heat tool I use is my hair dryer, and I keep that on low heat, so I couldn't figure how I suddenly fried my hair with my dryer. Luckily, it wasn't really fried -- it just looked fried from this product. When I washed my hair and styled without it, my old hair was still there. This spray is now in the trash.