What's the difference between the round Revlon One-Step and the paddle version?

The classic oval/paddle Revlon One-Step Volumizer is wider and faster for medium-to-long hair and creates a soft bend at the ends. The Root Booster round-brush version is smaller and aimed at lift at the crown for finer or shorter hair. Reviewers with thick, long hair tend to prefer the paddle; reviewers with fine, flat hair tend to prefer the round.