It took a lot longer than I was expecting and tbh I find it much better on already straightened or tonged second-day hair. If I just use the BBH I find it looks fabulous for about half an hour and then it goes frizzy. This doesn't happen when I blow dry with a brush and hairdryer so I can only assume the tension and heat aren't high enough.
My hair is really curly and messy and I find it great. My tip is to take your time to divide your hair in sections and start from the back. It takes a bit long but for me is easier, cheaper and quicker than going to the hairdressers so I don't mind.