I had previously written a pretty scathing review of this product in a hurry, and I think it deserves a better, more detailed treatment. Here goes!
My hair is long, thick, and curly (2c on top, 3a mid, and 3b underneath), and it frizzes easily. I can get a silky blow dry with just a round brush and some elbow grease, no product. I've had keratin treatments done, and really loved them. But I've been lazy about them for the past couple of years, so this product seemed like it could be a nice (and cheaper!) alternative.
My review is based on three uses over the course of two weeks. The first thing I noticed was that the texture was a bit gummy. Next, I found that it did indeed make it easier to straighten (and seemed to dry a bit faster in general). However, it left me with a texture that I wasn't happy with. The ends felt coarse and sort of puffy (which was never a problem for me before). There wasn't the same level of sleek silkiness. It did have fine shine and volume, but there was no movement. From my ears down my hair felt like a mass.
Frizz-wise, the shape held up, without any crazy expansion (I'm in the south, and it's definitely a good place to judge this), but I have gotten some overnight wavies close to the nape on the under layer.
Overall, I'm not crazy about this because it just gave my hair a very unappealing texture- sort of like what you would get with an amateur blowout. And while it did hold off frizz, I felt the trade-off wasn't worth it. Just didnt feel like my best hair. I can only imagine that over time this would get worse for me with the cumulative effect.
I might keep this in mind for a special event if I knew I'd be facing hair-wrecking humidity, but otherwise I think keratin is still the best overall remedy for the issues this product is targeting.