I got one and hate it. I have naturally wavy hair, which I really like. But every time I went to get my hair colored, they’d blow it out straight, and I’d get loads of compliments on it.
So finally I sprang the $400 it costs here. It’s a long process and the stylist wears a mask over his nose and mouth while applying it, but didn’t offer me one for some reason. 
Now it was probably partly my fault for not confirming, but I thought this would be like a straight perm–as in, I’d wake up every morning with my hair silky and straight like after a blow out. NO. All it does, as the stylist told me, is coat my hair so that it isn’t frizzy and is EASIER to blow out. WTF? I don’t want to sit there with blow dryer and flat iron every morning; that’s what the Brazilian is supposed to do!
I tried blowing it out once, but you really have to work hard with the brush, pulling and drying thoroughly, to get it straight. Otherwise it looks like crap.
I used to be able to go 2-3 days between shampoos, but now with this nasty coating, my hair looks greasy and limp. I can’t put too much product on it, since it already looks kind of nast.
Plus I have to use this special (ka-CHING!) shampoo/treatment, as (this could be horsesh*t, don’t know for sure) regular shampoo will cause the treatment to wash away faster.
I’m going in for another coloring tomorrow, and will get him to teach me how to blow it out, and will go buy a flat iron. Because unlike with my regular wavy hair, I can’t just wash it, scrunch it with some stuff, and be out the door. BAH!