Review (3/5): Not as easy as hoped, and with somewhat disappointing results
This sounded like it would be fast and easy, but it really doesn't work for my hair. You still have to part your hair into fairly thin sections, just as with a curling or straightening iron, and each section takes two or three strokes before it lies straight and curves under a bit. Then even if you get it to curve under, it doesn't last. The brush doesn't leave my (colored and highlighted) hair sleek and smooth--instead it leaves it kind of fluffy and frizzy.
The instructions say to use it only on clean hair, not hair with any product build-up on it, and this is absolutely true! If you have any hairspray on your hair--like if you try to use the brush on a day when you haven't just washed your hair, the brush will not go through. It kind of gets glued into your hair and you have to struggle to get it out, with some tearing and popping sounds as you do so, and an even frizzier appearance afterwards. So for me, it's back to the straightening iron.