A friend gave this to me after she bought it and didn't use it at all. My hair is naturally very fine and straight, and also holds styles really well. The crimper itself has very small grooves, which makes it really thin, light and easy to use. It didn't take long to crimp my whole head of roots, as I don't have that much hair, and I found it gave really nice natural volume (not eighties, but still nice). I wouldn't recommend it for thick heavy hair, as I can't imagine making it a massive difference, and I wouldn't pay the £25 my friend did.
Was so excited to get the Babyliss Root Boost. Love the big voluminous hair and thought this was the answer to my prayers. It's a cute looking crimper - the plates have smaller grooves though that a normal crimper. I paid €24.99 for this....and it is absolutely useless. Makes no difference to my hair at all and is just too time consuming. Better off just getting a decent back combing brush to be honest.